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Venom and the Good Life in Tarantula Hawks (Hymenoptera: Pompilidae): How to Eat, Not be Eaten, and Live Long
Abstract
Tarantula hawk wasps in the genera Pepsis and Hemipepsis are conspicuous elements of Southwestern U. S. and the Neotropics where they often appear oblivious to potential predators while they actively forage for nectar or search for prey. Tarantula hawks produce large quantities of venom and their stings produce immediate, intense, excruciating short term pain in envenomed humans. Although the instantaneous pain of a tarantula hawk sting is the greatest recorded for any stinging insect, the venom itself lacks meaningful vertebrate toxicity. The respective lethalities of 65 and 120 mg/kg in mice for the venoms of Pepsis formosa pattoni and P. thisbe reveal that the defensive value of stings and venom of these species is based entirely upon pain. This pain confers near absolute protection from vertebrate predators. The pain also forms an enabling basis for the evolution of aposematic coloration, aposematic odor, and a huge mimicry complex involving most species of tarantula hawks and numerous flies, beetles, moths, acridid grasshoppers, and other Hymenoptera. Tarantula hawks form mixed-species, both-sex aggregations that appear defensive in nature and likely aid in the location of resources and mating opportunities for some species. Because tarantula hawks have no meaningful predators, selection pressure appears to have favored long life spans. Long-lived individuals may then function as aposematic models; thereby decreasing predatory attacks by vertebrate predators directed toward wasp kin and future offspring. This suite of defensive adaptations has enabled tarantula hawks to forage and behave with near impunity and to maximize their food and reproduction while having long adult lives virtually free from predation.
... The sting apparatus of the Aculeata (ants, bees, and wasps) is an anatomical and physiological derivative of the ovipositor in female Hymenoptera, able to penetrate the skin of vertebrate predators and inject pain-inducing venom (Shing and Erickson, 1982). In the Hymenoptera, the apparatus is theorized to have initially evolved in solitary wasps in the role of paralyzing prey, a behavior observable in extant solitary wasps (Schmidt, 2004). However, in addition to using the sting apparatus during foraging, non-social hunting wasps (e.g., Pompilidae and Mutilidae) may sting vertebrate predators in self-defense, injecting highly painful venomous cocktails (Schmidt, 2016). ...
... However, in addition to using the sting apparatus during foraging, non-social hunting wasps (e.g., Pompilidae and Mutilidae) may sting vertebrate predators in self-defense, injecting highly painful venomous cocktails (Schmidt, 2016). This defense mechanism helps to explain why non-social wasps seems to have very few natural predators (Schmidt and Blum, 1977;Schmidt, 2004). ...
Social insects are well known for their aggressive (stinging) responses to a nest disturbance. Still, colonies are attacked due to the high-protein brood cached in their nests. Social wasps have evolved a variety of defense mechanisms to exclude predators, including nest construction and coordinated stinging response. Which predatory pressures have shaped the defensive strategies displayed by social wasps to protect their colonies? We reviewed the literature and explored social media to compare direct and indirect (claims and inferences) evidence of predators attacking individuals and colonies of wasps. Individual foraging wasps are predominantly preyed upon by birds and other arthropods, whereas predators on wasp brood vary across subfamilies of Vespidae. Polistinae wasps are predominantly preyed upon by ants and Passeriformes birds, whereas Vespinae are predominantly preyed upon by badgers, bears, and hawks. Ants and hornets are the primary predators of Stenogastrinae colonies. The probability of predation by these five main Orders of predators varies across continents. However, biogeographical variation in prey–predator trends was best predicted by climate (temperate vs. tropical). In social wasps’ evolutionary history, when colonies were small, predation pressure likely came from small mammals, lizards, or birds. As colonies evolved larger size and larger rewards for predators, the increased predation pressure likely selected for more effective defensive responses. Today, primary predators of large wasp colonies seem to be highly adapted to resist or avoid aggressive nest defense, such as large birds and mammals (which were not yet present when eusociality evolved in wasps), and ants.
... These wasps are one of the top insects in the world that can deliver an incredibly painful sting. This sting is described as "instantaneous, electrifying, excruciating, and totally debilitating" by the Schmidt Pain Index (Schmidt 2004). In fact, the pain is so intense that it is best to recommend to the person who has just been stung to "lay down and scream" as there is no way to aid in the immediate and intense pain an afflicted person experiences and during such an experience is more likely to harm themselves by running and flailing wildly than simply laying down and waiting for the pain to cease (Schmidt 2004). ...
... This sting is described as "instantaneous, electrifying, excruciating, and totally debilitating" by the Schmidt Pain Index (Schmidt 2004). In fact, the pain is so intense that it is best to recommend to the person who has just been stung to "lay down and scream" as there is no way to aid in the immediate and intense pain an afflicted person experiences and during such an experience is more likely to harm themselves by running and flailing wildly than simply laying down and waiting for the pain to cease (Schmidt 2004). Tarantula hawk wasps are holometabolous, just like all insects in the order Hymenoptera. ...
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... Sting and mesosomal lengths are given in mm and relative sting length is a ratio of sting length/mesosomal length. Sociality, host data, toxicity, and pain are derived from the literature (Brothers & Finnamore, 1993;Schmidt, 1986aSchmidt, , 1986bSchmidt, , 1990aSchmidt, , 2004Schmidt, , 2016Schmidt, Blum & Overal, 1980, 1986Starr, 1985). Toxicity data were not available for all taxa, but where possible, toxicity data for closely related species (within the same genus) was averaged for the genus and included in the table (e.g., Polistes). ...
... Measures of host preference, toxicity, and pain were derived from the literature (Brothers & Finnamore, 1993;Schmidt, 1986aSchmidt, , 1986bSchmidt, , 1990aSchmidt, , 2004Schmidt, , 2016Schmidt, Blum & Overal, 1980, 1986Starr, 1985). Toxicity measures were only available for a handful of species (Table 1). ...
The stings of bees, wasps, and ants are something that catches the attention of anyone that experiences them. While many recent studies have focused on the pain inflicted by the stings of various stinging wasps, bees, or ants (Hymenoptera: Aculeata), little is known about how the length of the sting itself varies between species. Here, we investigate the sting length of a variety of aculeate wasps, and compare that to reported pain and toxicity values. We find that velvet ants (Hymenoptera: Mutillidae) have the longest sting compared to their body size out of any bee, wasp, or ant species. We also find that there is no link between relative sting length and pain; however, we did find an inverse relationship between relative sting length and toxicity with taxa having shorter relative stings being more toxic. While we found a significant relationship between host use and relative sting length, we suggest that the long sting length of the velvet ants is also related to their suite of defenses to avoid predation.
... In March 1800, Alexander von Humboldt observed the extraordinary spectacle of native fisherman collecting electric eels (Electrophorus electricus) by "fishing with horses" [von Humboldt A (1807) Ann Phys 25: [34][35][36][37][38][39][40][41][42][43]. The strategy was to herd horses into a pool containing electric eels, provoking the eels to attack by pressing themselves against the horses while discharging. ...
... In the latter case, the activation of afferent (sensory) pathways is irrelevant to the eel, but when leaping to shock large animals, the aversive sensory experience of afferent activation (combined with induced tetanus) likely plays a key role in deterrence. In this context, the eel's electrical defense may parallel the pain-inducing venoms of some insects and arachnids that have a primarily deterrent function but do not cause tissue damage (38,39). The possibility that eels use the leaping strategy to hunt is untenable because they swallow food whole, would not benefit from stunning large animals, and never bit or tried to swallow the large conductors during or after the leap. ...
Significance
Electric eels are shown to leap from the water to directly electrify threats. This shocking behavior likely allows electric eels to defend themselves during the Amazonian dry season, when they may be found in small pools and in danger of predation. The results support Alexander von Humboldt’s story of electric eels attacking horses that had been herded into a muddy pool during the dry season in 1800. The finding highlights sophisticated behaviors that have evolved in concert with the eel’s powerful electrical organs.
... Nine spider wasps in the genus Psorthaspis (Pompilidae) closely resemble velvet ant color patterns [16], and thus might be participating in the velvet ant mimicry complex. Because spider wasps are defended with a sting that invokes some of the most intense, instantaneous pain among stinging insects [17], and velvet ants and Psorthaspis spider wasps are attacked by some of the same predators (i.e., frogs, lizards and mammals) [18][19][20][21][22], Psorthaspis spider wasps and velvet ants could be Müllerian mimics of each other. However, the resemblance of Psorthaspis spider wasps to velvet ants, and the potential fit of both wasps to the same mimicry complex have never been quantified. ...
... These spider wasps use trapdoor spiders of the family Ctenizidae as hosts [29]. Even though the venom is primarily used to paralyze the host, the sting of both spider wasps and velvet ants also can be a deterrent to predation [10,17]. ...
Recent studies have delineated a large Nearctic Müllerian mimicry complex in Dasymutilla velvet ants. Psorthaspis spider wasps live in areas where this mimicry complex is found and are phenotypically similar to Dasymutilla. We tested the idea that Psorthaspis spider wasps are participating in the Dasymutilla mimicry complex and that they codiverged with Dasymutilla. We performed morphometric analyses and human perception tests, and tabulated distributional records to determine the fit of Psorthaspis to the Dasymutilla mimicry complex. We inferred a dated phylogeny using nuclear molecular markers (28S, elongation factor 1-alpha, long-wavelength rhodopsin and wingless) for Psorthaspis species and compared it to a dated phylogeny of Dasymutilla. We tested for codivergence between the two groups using two statistical analyses. Our results show that Psorthaspis spider wasps are morphologically similar to the Dasymutilla mimicry rings. In addition, our tests indicate that Psorthaspis and Dasymutilla codiverged to produce similar color patterns. This study expands the breadth of the Dasymutilla Müllerian mimicry complex and provides insights about how codivergence influenced the evolution of mimicry in these groups.
... Pain is a major component of aculeate defences (Schmidt, Blum & Overal, 1980;Starr, 1985;Schmidt, 2004Schmidt, , 2019, and is likely important for predator learning. Although studying pain is not straightforward, in part due to the difficulty of objectively quantifying 'pain', we believe that such research will yield novel material for mimicry theory and testing. ...
Many bees and stinging wasps, or aculeates, exhibit striking colour patterns or conspicuous coloration, such as black and yellow stripes. Such coloration is often interpreted as an aposematic signal advertising aculeate defences: the venomous sting. Aposematism can lead to Müllerian mimicry, the convergence of signals among different species unpalatable to predators. Müllerian mimicry has been extensively studied, notably on Neotropical butterflies and poison frogs. However, although a very high number of aculeate species harbour putative aposematic signals, aculeates are under-represented in mimicry studies. Here, we review the literature on mimicry rings that include bee and stinging wasp species. We report over a hundred described mimicry rings, involving a thousand species that belong to 19 aculeate families. These mimicry rings are found all throughout the world. Most importantly, we identify remaining knowledge gaps and unanswered questions related to the study of Müllerian mimicry in aculeates. Some of these questions are specific to aculeate models, such as the impact of sociality and of sexual dimorphism in defence levels on mimicry dynamics. Our review shows that aculeates may be one of the most diverse groups of organisms engaging in Müllerian mimicry and that the diversity of aculeate Müllerian mimetic interactions is currently under-explored. Thus, aculeates represent a new and major model system to study the evolution of Müllerian mimicry. Finally, aculeates are important pollinators and the global decline of pollinating insects raises considerable concern. In this context, a better understanding of the impact of Müllerian mimicry on aculeate communities may help design strategies for pollinator conservation, thereby providing future directions for evolutionary research.
... In most Aculeata, females escape predators because of the pain induced by their sting and by the injected 83 venom (Schmidt, 2004). The stinger in wasp and bee females may then induce a substantial difference in 84 survival between defended females and undefended males, in habitats where predators are common. ...
A bstract
Positive ecological interactions can play a role in community structure and species co-existence. A well-documented case of mutualistic interaction is Mullerian mimicry, the convergence of colour pattern in defended species living in sympatry. By reducing predation pressure, Mullerian mimicry may limit local extinction risks of defended species, but this positive effect can be weakened by undefended mimics (Batesian mimicry). While mimicry was well-studied in neotropical butterflies, it remains surprisingly poorly studied in wasps and bees (Hymenoptera: Aculeata). However, only females are defended in Aculeata and this female-limited defence may modulate the effect of Mullerian mimicry on extinction risks. Here, we focus on the effect of Mullerian mimicry on extinction risk in Aculeata, using a population dynamics model for two species. We show that Mullerian mimicry has a positive effect on species co-existence, but this effect depends on the sex-ratio. We found that the probability of extinction increases as the proportion of undefended males increases in the population, however co-existence still occurs if females are sufficiently abundant or noxious. Furthermore, we detected a destabilising effect of dual sex-limited mimicry (when each sex resembles a different model) on species co-existence. In a context of massive population decline caused by anthropic activities, our findings highlight the potential importance of Mullerian mimicry as an overlooked mechanism linked to extinction risk in wasp and bee species.
... DSLM has scarcely been studied at all since its description over 50 years ago and may also be best addressed in aculeate systems in which multiple distinct mimetic patterns are known to overlap, such as with velvet ants (Wilson et al., 2015(Wilson et al., , 2018. Promising aculeate groups for future studies on mimicry include large carpenter bees (Blaimer et al., 2018), vespid wasps (Perrard et al., 2014;Marchini et al., 2016), and spider wasps (Schmidt, 2004). ...
Aposematism and mimicry are complex phenomena which have been studied extensively; however, much of our knowledge comes from just a few focal groups, especially butterflies. Aposematic species combine a warning signal with a secondary defense that reduces their profitability as prey. Aculeate hymenopterans are an extremely diverse lineage defined by the modification of the ovipositor into a stinger which represents a potent defense against predators. Aculeates are often brightly colored and broadly mimicked by members of other arthropod groups including Diptera, Lepidoptera, Coleoptera, and Araneae. However, aculeates are surprisingly understudied as aposematic and mimetic model organisms. Recent studies have described novel pigments contributing to warning coloration in insects and identified changes in cis -regulatory elements as potential drivers of color pattern evolution. Many biotic and abiotic factors contribute to the evolution and maintenance of conspicuous color patterns. Predator distribution and diversity seem to influence the phenotypic diversity of aposematic velvet ants while studies on bumble bees underscore the importance of intermediate mimetic phenotypes in transition zones between putative mimicry rings. Aculeate hymenopterans are attractive models for studying sex-based intraspecific mimicry as male aculeates lack the defense conferred by the females’ stinger. In some species, evolution of male and female color patterns appears to be decoupled. Future studies on aposematic aculeates and their associated mimics hold great promise for unraveling outstanding questions about the evolution of conspicuous color patterns and the factors which determine the composition and distribution of mimetic communities.
... Most of these systems appear to attract the wasps via scent signals [76,81] and some have specialized enough to make use of specific deceptive tactics by mimicking prey or mates [73,79]. The venoms of pompilids are notoriously painful [82] and the genus Pepsis is one of the few taxa that has been rated as a four (out of four) on the Schmidt Sting Pain Index (a subjective ranking of the pain caused by various insect stings) [83]. However, this defensive use is not the primary evolutionary purpose of these venoms. ...
Parasitoid wasps represent the plurality of venomous animals, but have received extremely little research in proportion to this taxonomic diversity. The lion’s share of investigation into insect venoms has focused on eusocial hymenopterans, but even this small sampling shows great promise for the development of new active substances. The family Pompilidae is known as the spider wasps because of their reproductive habits which include hunting for spiders, delivering a paralyzing sting, and entombing them in burrows with one of the wasp’s eggs to serve as food for the developing larva. The largest members of this family, especially the tarantula hawks of the genus Pepsis, have attained notoriety for their large size, dramatic coloration, long-term paralysis of their prey, and incredibly painful defensive stings. In this paper we review the existing research regarding the composition and function of pompilid venoms, discuss parallels from other venom literatures, identify possible avenues for the adaptation of pompilid toxins towards human purposes, and future directions of inquiry for the field.
... Pain could be useful for defensive purposes but, when considering predation, fast pain induction could represent an evolutionary conflict. While on one hand pain induction could be a good strategy to deter predators from pursuing their attack [287,288], on the other hand pain could enhance prey struggling and make establishing a firm grip on the prey more difficult [51,154,288]. A venom that is used both to incapacitate prey and deter predators should therefore induce pain in its main predators, and paralysis or death in prey. ...
Scorpions possess two systems of weapons: the pincers (chelae) and the stinger (telson). These are placed on anatomically and developmentally well separated parts of the body, that is, the oral appendages and at the end of the body axis. The otherwise conserved body plan of scorpions varies most in the shape and relative dimensions of these two weapon systems, both across species and in some cases between the sexes. We review the literature on the ecological function of these two weapon systems in each of three contexts of usage: (i) predation, (ii) defense and (iii) sexual contests. In the latter context, we will also discuss their usage in mating. We first provide a comparative background for each of these contexts of usage by giving examples of other weapon systems from across the animal kingdom. Then, we discuss the pertinent aspects of the anatomy of the weapon systems, particularly those aspects relevant to their functioning in their ecological roles. The literature on the functioning and ecological role of both the chelae and the telson is discussed in detail, again organized by context of usage. Particular emphasis is given on the differences in morphology or usage between species or higher taxonomic groups, or between genders, as such cases are most insightful to understand the roles of each of the two distinct weapon systems of the scorpions and their evolutionary interactions. We aimed to synthesize the literature while minimizing conjecture, but also to point out gaps in the literature and potential future research opportunities.
... Here again, absolute distinctions between venom types and functions warrant caution [24], as paralytic toxins are employed by some cone snails as a defense against their fish and cephalopod predators [10], while certain buthid scorpions deploy mammal-specific neurotoxins that disrupt muscle function in these vertebrate enemies [25,26]. These caveats aside, we are unaware of any algogenic venoms having evolved for predatory purposes, as pain is unnecessary for immobilizing one's prey [27]. Indeed, in the context of feeding, venom components designed to cause immediate pain might be maladaptive if such toxins are costly to produce or render subjugation of the prey more difficult [23]. ...
Pain, though unpleasant, is adaptive in calling an animal’s attention to potential tissue damage. A long list of animals representing diverse taxa possess venom-mediated, pain-inducing bites or stings that work by co-opting the pain-sensing pathways of potential enemies. Typically, such venoms include toxins that cause tissue damage or disrupt neuronal activity, rendering painful stings honest indicators of harm. But could pain alone be sufficient for deterring a hungry predator? Some venomologists have argued “no”; predators, in the absence of injury, would “see through” the bluff of a painful but otherwise benign sting or bite. Because most algogenic venoms are also toxic (although not vice versa), it has been difficult to disentangle the relative contributions of each component to predator deterrence. Southern grasshopper mice (Onychomys torridus) are voracious predators of arthropods, feeding on a diversity of scorpion species whose stings vary in painfulness, including painful Arizona bark scorpions (Centruroides sculpturatus) and essentially painless stripe-tailed scorpions (Paravaejovis spinigerus). Moreover, southern grasshopper mice have evolved resistance to the lethal toxins in bark scorpion venom, rendering a sting from these scorpions painful but harmless. Results from a series of laboratory experiments demonstrate that painful stings matter. Grasshopper mice preferred to prey on stripe-tailed scorpions rather than bark scorpions when both species could sting; the preference disappeared when each species had their stingers blocked. A painful sting therefore appears necessary for a scorpion to deter a hungry grasshopper mouse, but it may not always be sufficient: after first attacking and consuming a painless stripe-tailed scorpion, many grasshopper mice went on to attack, kill, and eat a bark scorpion even when the scorpion was capable of stinging. Defensive venoms that result in tissue damage or neurological dysfunction may, thus, be required to condition greater aversion than venoms causing pain alone.
... In a few species that use venom for paralyzing prey, the venom might also be used for defense. These venoms could contain pain-inducing constituents that would be predicted to be non-paralytic, but might be toxic or lethal to potential predators [9,10]. ...
Pain is a natural bioassay for detecting and quantifying biological activities of venoms. The painfulness of stings delivered by ants, wasps, and bees can be easily measured in the field or lab using the stinging insect pain scale that rates the pain intensity from 1 to 4, with 1 being minor pain, and 4 being extreme, debilitating, excruciating pain. The painfulness of stings of 96 species of stinging insects and the lethalities of the venoms of 90 species was determined and utilized for pinpointing future directions for investigating venoms having pharmaceutically active principles that could benefit humanity. The findings suggest several under- or unexplored insect venoms worthy of future investigations, including: those that have exceedingly painful venoms, yet with extremely low lethality—tarantula hawk wasps (Pepsis) and velvet ants (Mutillidae); those that have extremely lethal venoms, yet induce very little pain—the ants, Daceton and Tetraponera; and those that have venomous stings and are both painful and lethal—the ants Pogonomyrmex, Paraponera, Myrmecia, Neoponera, and the social wasps Synoeca, Agelaia, and Brachygastra. Taken together, and separately, sting pain and venom lethality point to promising directions for mining of pharmaceutically active components derived from insect venoms.
... El tamaño de las hembras les ha creado una reputación de ser culpables de unas de las picaduras más dolorosas del Reino Animal. Para Schmidt (2004) una picadura muy dolorosa, pero poco mortal, es un compromiso evolutivo en Pepsis para disuadir depredadores y paralizar arañas sin matarlas. De hecho, los enemigos naturales de Pepsis son muy escasos y otros insectos se benefician de su picadura dolorosa por mimetismo batesiano, como saltamontes Tettigonidae, chinches asesinas Reduviiidae o moscas Asilidae. ...
Las avispas cazadoras de arañas son una familia de himenópteros (Pompilidae) cuyas hembras cazan exclusivamente arañas para alimentar a su progenie, siendo siempre un huevo por araña paralizada. Hay una notable diversidad de tamaños, desde algunas pequeñas de pocos milímetros hasta las gigantescas Pepsis, cazadoras de tarántulas cuyas hembras pueden sobrepasar los 7 cm de longitud y 13 cm. de envergadura de alas. La fauna de Colombia no ha sido objeto de investigación hasta el presente aporte, donde se ofrece una introducción general a la sistemática y biología de la familia, morfología, y claves ilustradas para las subfamilias y géneros en el país. Se presenta una sinopsis de los géneros conocidos para Colombia, con fotografías de hembra y macho, claves para especies (en la mayoría de géneros) y mapas de distribución.
... The evolution of priestly castes and horrific human sacrifice is comparable in core respects to the evolution of Tarantula hawk wasps (Hymenoptera: Pompilidae). These organisms, large brightly colored invertebrates that inhabit the southwestern United States, are "among the most conspicuous insects on earth" (Schmidt, 2004). Though the wasp's venom is not lethal, its sting tops the subjective pain scale (Schmidt, 1995) and has been described as "totally unacceptable." ...
This chapter describes an evolutionary model of religion called “charismatic signaling.” The theory focuses on features of religion that express automated within-group cooperation—that is, cooperation that does not rely on strategic reasoning or explicit social prediction. The model is interesting because it explains otherwise puzzling features of religious systems. Such puzzles range from intrinsic religious motivations to ritual human sacrifice as evolved adaptations for social coordination. An additional virtue of the model is that it explains the reliability of cooperation with strangers who cannot observe or assess cooperative intentions directly or by reputation. The chapter describes the intellectual motivations for charismatic signaling theory and outlines ethnographic and historical puzzles the theory solves.
... Some Pepsis species and the bullet ant Paraponera clavata (Fabricius) deliver the most painful stings known (Schmidt 2016). Schmidt's (2004) advice to any unfortunate victim stung by one is to "lie down and scream. " The intense pain, however, lasts only a few minutes. ...
The most widely recognized hymenopterans – ants, bees, and wasps or hornets – have long been part of art, ritual, and folklore worldwide. Both extant and extinct Hymenoptera were classified into two broad groups, the Symphyta and Apocrita. The Symphyta include the most primitive hymenopterans and comprise almost 5% of the extant Hymenoptera. The Apocrita include about 96% of the Hymenoptera and are subdivided into the Aculeata, which include familiar species such as ants, social wasps, and bees, and the Parasitica, a diverse and abundant group of usually small, inconspicuous species, most of which parasitize insects and spiders. Hymenoptera have diversified into various morphological forms and ways of life and might be the largest order of insects. The important works include a discussion of hymenopteran diversity and importance, overviews of the Symphyta, biology of the Parasitica and solitary Aculeata, and family identification keys and diagnoses for the world.
... Objective three relates to one of the presumed differences in venoms used for securing prey versus those used for deterring potential predators, that is, pain. Pain-inducing toxins are thought to have evolved primarily, if not solely, for defense rather than for feeding (Schmidt 1990(Schmidt , 2004. The primary prey of scorpions are arthropods (McCormick and Polis 1990), for which toxins causing quick paralysis, not pain, would be most effective. ...
Studies of venom variability have advanced from describing the mechanisms of action and relative potency of medically important toxins to understanding the ecological and evolutionary causes of the variability itself. While most studies have focused on differences in venoms among taxa, populations, or age-classes, there may be intersexual effects as well. Striped bark scorpions (Centruroides vittatus) provide a good model for examining sex differences in venom composition and efficacy, as this species exhibits dramatic sexual dimorphism in both size and defensive behavior; when threatened by an enemy, larger, slower females stand and fight while smaller, fleeter males prefer to run. We here add evidence suggesting that male and female C. vittatus indeed have different defensive propensities; when threatened via an electrical stimulus, females were more likely to sting than were males. We reasoned that intersexual differences in defensive phenotypes would select for venoms with different functions in the two sexes; female venoms should be effective at predator deterrence, whereas male venoms, less utilized defensively, might be better suited to capturing prey or courting females. This rationale led to our predictions that females would inject more venom and/or possess more painful venom than males. We were wrong. While females do inject more venom than males in a defensive sting, females are also larger; when adjusted for body size, male and female C. vittatus commit equal masses of venom in a sting to a potential enemy. Additionally, house mice (Mus musculus) find an injection of male venom more irritating than an equal amount of female venom, likely because male venom contains more of the toxins that induce pain. Taken together, our results suggest that identifying the ultimate causes of venom variability will, as we move beyond adaptive storytelling, be hard-won.
... Examples of the latter group are the Pompilidae, a cosmopolitan family of spider-hunting wasps, of which the most well-known members are the eye-catching tarantula hawks of the New World genus Pepsis [5]. Currently about 5000 predominately tropical and subtropical species are described [6]. ...
Hymenoptera show a great variation in reproductive potential and nesting behavior, from thousands of eggs in sawflies to just a dozen in nest-provisioning wasps. Reduction in reproductive potential in evolutionary derived Hymenoptera is often facilitated by advanced behavioral mechanisms and nesting strategies. Here we describe a surprising nesting behavior that was previously unknown in the entire animal kingdom: the use of a vestibular cell filled with dead ants in a new spider wasp (Hymenoptera: Pompilidae) species collected with trap nests in South-East China. We scientifically describe the 'Bone-house Wasp' as Deuteragenia ossarium sp. nov., named after graveyard bone-houses or ossuaries. We show that D. ossarium nests are less vulnerable to natural enemies than nests of other sympatric trap-nesting wasps, suggesting an effective nest protection strategy, most likely by utilizing chemical cues emanating from the dead ants.
... Humans, therefore, rarely are stung by solitary wasps, and their venom is not designed to cause pain, though there are notable exceptions in the Bethylidae, Mutillidae, and Pompilidae. Some Pepsis species and the bullet ant Paraponera clavata deliver the most painful stings known (Schmidt 2004). Schmidt's advice to any victim stung by one is to 'lie down and scream'. ...
Evolution and Higher ClassificationNumbers of Species and IndividualsMorphological and Biological DiversityImportance to HumansTaxonomic DiversitySocietal Benefits and Detriments of HymenopteraConclusions
AcknowledgmentsReferences
... Linsley et al. (1961) for example describe a series of "lycid complexes" that include collections of unpalatable lycid beetles, arctiid moths, parasitic hymenoptera and flies, all of which are orange in coloration with black tips (see Fig. 1a,b). Similarly, tarantula hawk wasps in the genera Pepsis and Hemipepsis have some of the most painful stings known to man and form Müllerian (and Batesian) mimicry complexes with many other species of stinging tarantula hawks, as well as numerous flies, beetles and moths (Schmidt 2004). Cross-order examples of Müllerian mimicry are not uncommon and provide some of the most spectacular examples of adaptive resemblance, including the co-mimicry of tiger beetles and wasps (Schultz 2001) and the co-mimicry of moths and wasps (Weller et al. 2000, Fig. 1c,d). ...
It is now 130 years since Fritz Müller proposed an evolutionary explanation for the close similarity of co-existing unpalatable prey species, a phenomenon now known as Müllerian mimicry. Müller's hypothesis was that unpalatable species evolve a similar appearance to reduce the mortality involved in training predators to avoid them, and he backed up his arguments with a mathematical model in which predators attack a fixed number (n) of each distinct unpalatable type in a given season before avoiding them. Here, I review what has since been discovered about Müllerian mimicry and consider in particular its relationship to other forms of mimicry. Müller's specific model of associative learning involving a "fixed n" in a given season has not been supported, and several experiments now suggest that two distinct unpalatable prey types may be just as easy to learn to avoid as one. Nevertheless, Müller's general insight that novel unpalatable forms have higher mortality than common unpalatable forms as a result of predation has been well supported by field experiments. From its inception, there has been a heated debate over the nature of the relationship between Müllerian co-mimics that differ in their level of defence. There is now a growing awareness that this relationship can be mediated by many factors, including synergistic effects between co-mimics that differ in their mode of defence, rates of generalisation among warning signals and concomitant changes in prey density as mimicry evolves. I highlight areas for future enquiry, including the possibility of Müllerian mimicry systems based on profitability rather than unprofitability and the co-evolution of defence.
The ecology and conservation status of some Irish aculeate Hymenoptera species, such as bees, are well known but comparatively little information is available regarding the natural history of solitary wasps, which account for a large proportion of the Irish aculeate fauna. Spider wasps (Hymenoptera: Pompilidae) are a globally diverse family of solitary wasps that prey exclusively upon spiders. Most species provision nests with a paralysed spider, which serves as the sole food source for developing larvae. Adults are mostly nectar-feeders and many species may contribute to pollination. Here we present the first complete catalogue of the spider wasps of Ireland, the recorded distribution and temporal activity of each species, and short accounts of other aspects of the ecology of Irish Pompilidae. Irish spider wasp records were collated from voucher specimens held by the National Museum of Ireland, published literature sources and records provided by the National Biodiversity Data Centre (ROI), CEDaR and the National Biodiversity Network (NBN) Atlas (NI) to produce maps of the known distribution of each species. Ireland is home to thirteen confirmed Pompilidae species that may be considered native, and an additional species for which the Irish status remains unconfirmed until further specimens can be collected. Brief accounts of the ecology and behaviour of each Irish species are provided.
Arthropod venoms may be considered important sources of bioactive molecules; however, technical difficulties, such as venom extraction and homogeneity may impair the biochemical identification of new molecules. In this context, we have developed a method to maintain wasps in captivity that allows the collection of the venom, without use of chemical, mechanical or electrical stimuli. The crude venom was analyzed by RP-HPLC-ESIQ-ToF and 20 peptides were identified by de novo peptide sequencing, among them Eumenine-Mastoparan and a Ponericin-G2-simile peptide.
Parasitoid wasps are a unique group among venomous organisms. In contrast to the common venom functions of predation and defense, female parasitoid wasps use venom to manipulate the metabolism, development, and behavior of other arthropods for reproductive purposes. This provides a safe environment and nutrition for the next generation of wasps to feed and develop. Parasitoid wasp species diversity is estimated to be between 150,000 and 600,000 species, likely making them the largest group of venomous organisms. They parasitize all orders of Insecta and several taxa from Arachnida. Parasitoids display highly diverse morphologies and parasitic lifestyles. This diversity likely plays a strong role in the adaptive evolution of venom apparatus structures, venom genes, and venom functions. However, parasitoid wasps are underexplored and little represented in toxinology.
This chapter provides a background into evolution of parasitoid wasps and their parasitic lifestyle. The evolution of parasitoid venoms and their functions are discussed, and a comparison of venom functions in two major ecological categories, ectoparasitoids and endoparasitoids, is provided. Expanding on the standard gene duplication and recruitment model of toxin gene evolution, additional mechanisms are proposed. These include co-option, multifunctionalization, alternate splicing, and origins from lateral gene transfers or noncoding DNA. Novel tools such as RNA interference (RNAi) knockdown of parasitoid venom genes, combined with RNA sequencing of envenomated hosts, are proposed for venom function hypothesis testing and hypothesis generation. This chapter also addresses key questions concerning the future directions of parasitoid venom research.
Parasitoid wasps are a unique group among venomous organisms. In contrast to the common venom functions of predation and defense, female parasitoid wasps use venom to manipulate the metabolism, development, and behavior of other arthropods for reproductive purposes. This provides a safe environment and nutrition for the next generation of wasps to feed and develop. Parasitoid wasp species diversity is estimated to be between 150,000 and 600,000 species, likely making them the largest group of venomous organisms. They parasitize all orders of Insecta and several taxa from Arachnida. Parasitoids display highly diverse morphologies and parasitic lifestyles. This diversity likely plays a strong role in the adaptive evolution of venom apparatus structures, venom genes, and venom functions. However, parasitoid wasps are underexplored and little represented in toxinology.
This chapter provides a background into evolution of parasitoid wasps and their parasitic lifestyle. The evolution of parasitoid venoms and their functions are discussed, and a comparison of venom functions in two major ecological categories, ectoparasitoids and endoparasitoids, is provided. Expanding on the standard gene duplication and recruitment model of toxin gene evolution, additional mechanisms are proposed. These include co-option, multifunctionalization, alternate splicing, and origins from lateral gene transfers or noncoding DNA. Novel tools such as RNA interference (RNAi) knockdown of parasitoid venom genes, combined with RNA sequencing of envenomated hosts, are proposed for venom function hypothesis testing and hypothesis generation. This chapter also addresses key questions concerning the future directions of parasitoid venom research.
Parasitoid wasps are a unique group among venomous organisms. In contrast to the common venom functions of predation and defense, female parasitoid wasps use venom to manipulate the metabolism, development, and behavior of other arthropods for reproductive purposes. This provides a safe environment and nutrition for the next generation of wasps to feed and develop. Parasitoid wasp species diversity is estimated to be between 150,000 and 600,000 species, likely making them the largest group of venomous organisms. They parasitize all orders of Insecta and several taxa from Arachnida. Parasitoids display highly diverse morphologies and parasitic lifestyles. This diversity likely plays a strong role in the adaptive evolution of venom apparatus structures, venom genes, and venom functions. However, parasitoid wasps are underexplored and little represented in toxinology.
This chapter provides a background into evolution of parasitoid wasps and their parasitic lifestyle. The evolution of parasitoid venoms and their functions are discussed, and a comparison of venom functions in two major ecological categories, ectoparasitoids and endoparasitoids, is provided. Expanding on the standard gene duplication and recruitment model of toxin gene evolution, additional mechanisms are proposed. These include co-option, multifunctionalization, alternate splicing, and origins from lateral gene transfers or noncoding DNA. Novel tools such as RNA interference (RNAi) knockdown of parasitoid venom genes, combined with RNA sequencing of envenomated hosts, are proposed for venom function hypothesis testing and hypothesis generation. This chapter also addresses key questions concerning the future directions of parasitoid venom research.
Wasp venom characterization is of interest across multiple disciplines such as medicinal chemistry and evolutionary biology. A simple method is described herein to milk wasp venom without undue risks to the researcher. The wasps were immobilized by cooling for safe handling, restrained, and their venom was collected on parafilm. Bradykinin from Hemipepsis ustulata was identified by LC-MS/MS during method verification.
In this part the remaining 78 species of the genus Pepsis, belonging to ten species-groups, are described and figured, and their phylogenetics and biogeography are discussed. 14 of the species are described as new: P. achterbergi spec. nov., P. adonta spec. nov., P. boharti spec. nov., P. caliente spec. nov., P. dayi spec. nov., P. esmeralda spec. nov., P. ianthoides spec. nov., P. jamaicensis spec. nov., P. krombeini spec. nov., P. martini spec. nov., P. multichroma spec. nov., P. nanoides spec. nov., P. wahisi spec. nov., and P. willinki spec. nov. Three species-names, P. infuscata Spinola, 1841, P. lampas Lucas, 1895, and P. thoreyi Dahlbom, 1845, are recalled from synonymy. The following 293 names are newly synonymized (the valid names are listed first): P. atalanta Mocsáry, 1885 = P. nitens Mocsáry, 1894, P. mocsaryi Lucas, 1895; P. inclyta Lepeletier, 1845 = P. mutabilis Lepeletier, 1845, P. vagabunda Lepeletier, 1845, P. cupripennis Taschenberg, 1869, P. violaceipennis Mocsáry, 1885, P. clotho Mocsáry, 1888, P. spengeli Mocsáry, 1888, P. sickmanni Mocsáry, 1888, P. nireus Mocsáry, 1894, P. atrovirens Lucas, 1895, P. cerastes Lucas, 1895, P. pygidialis Brèthes, 1908, P. guaranitica Brèthes, 1908, P. parca Lucas, 1919, P. atahualpa Banks, 1946, opimicornis, Haupt, 1952, atropos, Haupt, 1952, azurea Haupt, 1952; crassicornis Mocsáry, 1885 = P. sappho Brèthes, 1908, P. nitocris Brèthes, 1908, P. vivida Brèthes, 1908, P. arechavaletai Brèthes, 1908, P. lynchii Brèthes, 1908, P. operosa Brèthes, 1908, P. ataraqua Banks, 1946, P. splendida Haupt, 1952; P. sommeri Dahlbom, 1845 = P. azteca Cameron, 1893; P. xanthocera Dahlbom, 1843 = P. nigrescens Smith, 1855, P. fulgidipennis Mocsáry, 1885, P. juno Brèthes, 1908, P. ismare Banks, 1946, P. nigroprasina Haupt, 1952; P. seifferti Lucas, 1895 = P. cornuta Lucas, 1895, P. moebiusi Lucas, 1895, P. stygia Lucas, 1895; P. luteicornis Fabricius, 1804 = P. strenua Erichson, 1848, P. tinctipennis Smith, 1873, P. citreicornis Mocsáry, 1894, P. venosa Banks, 1945, P. alector Banks, 1946; P. asteria Mocsáry, 1894 = P. luridicornis Brèthes, 1926; P. convexa Lucas, 1895 = P. humeralis Brèthes, 1914; P. helvolicornis Lucas, 1895 = P. bahiae Brèthes, 1914; P. vitripennis Smith, 1855 = P. obscura Lepeletier, 1845, P. amabilis Mocsáry, 1885, P. centralis Cameron, 1893, P. margarete Lucas, 1895, P. venezuelae Kaye, 1913, P. aeneipennis Banks, 1946, P. helenae Haupt, 1952, P. coeruleoviridis Haupt, 1952; P. fumipennis Smith, 1855 = P. pallidicornis Mocsáry, 1885; P. amyntas Mocsáry, 1885 = P. vicina Lucas, 1895, P. clarinervis Brèthes, 1908, P. amyntoides Lucas, 1919, P. eurydice Lucas, 1919; P. dimidiata Fabricius, 1804 = P. vittigera Lucas, 1897, P. argentina Brèthes, 1908, P. sanctaeannae Brèthes, 1908, P. virgo Brèthes, 1908, P. externa Brèthes, 1908, P. transversa Brèthes, 1908, P. cordubensis Brèthes, 1908, P. banghaasi Lucas, 1919; P. menechma Lepeletier, 1845 = P. elegans Lepeletier, 1845, P. dubitata Cresson, 1867, P. prismatica Smith, 1855, P. advena Mocsáry, 1885, cinctipennis Mocsáry, 1885, P. guatemalensis Cameron, 1893, P. nestor Mocsáry, 1894, P. nigricornis Mocsáry, 1894, P. auranticornis Lucas, 1895, P. fruhstorferi Lucas, 1895, P. concolor Lucas, 1895, P. cerberus Lucas, 1895, P. euchroma Lucas, 1895, P. nigrocincta Lucas, 1895, P. mordax Lucas, 1895, P. inermis Fox, 1898, P. roberti Brèthes, 1908, P. janira Brèthes, 1908, P. cultrata Brèthes, 1908, P. novitia Banks, 1921; P. decipiens Lucas, 1895 = P. similis Lucas, 1895; P. minarum Brèthes, 1914 = P. pulchra Brèthes, 1914; P. basifusca Lucas, 1895 = P. angustimarginata Viereck, 1908; P. chrysoptera Burmeister, 1872 = P. exigua Lucas, 1895, P. smaragdinula Lucas, 1895, P. nebulosa Lucas, 1895, P. karschi Lucas, 1895, P. anisitsii Brèthes, 1908, P. indistincta Brèthes, 1908, P. dimidiatipennis Brèthes, 1908, P. chloroptera Brèthes, 1908, P. culta Brèthes, 1908, P. recta Brèthes, 1908, P. tornowii Brèthes, 1908, P. schrottkyi Brèthes, 1908, P. itinerata Brèthes, 1908, P. miniata Brèthes, 1908, P. spegazzinii Brèthes, 1908, P. paulistana Brèthes, 1914, P. chloe Brèthes, 1914, P. coronaria Brèthes, 1914, P. semilucana Haupt, 1952, P. bruneipes Haupt, 1952, P. brachynotus Haupt, 1952, P. diagonalis Haupt, 1952, P. discrepans Haupt, 1952; P. elongata Lepeletier, 1845 = P. purpurascens Smith, 1855, P. fuscipennis Smith, 1873, P. longula Banks, 1946; P. australis Saussure, 1867 = P. centaurus Lucas, 1897; P. cyanescens Lepeletier, 1845 = P. micans Mocsáry, 1885, P. jucunda Mocsáry, 1885, P. balloui Banks, 1946, P. diversa Haupt, 1952; P. lampas Lucas, 1895 = P. venturii Schrottky, 1902; P. nitida Lepeletier, 1845 = P. lucidula Smith, 1855, P. vaualba Smith, 1855, P. pruinosa Mocsáry, 1894, P. cylindrica Lucas, 1895, P. andina Brèthes, 1908, P. dilatata Brèthes, 1908, P. holmbergi Brèthes, 1908, P. concava Brèthes, 1908, P. ephebus Brèthes, 1908, P. vaga Brèthes, 1908, P. fuscobasalis Brèthes, 1908, P. cordata Brèthes, 1914, P. impatiens Brèthes, 1914, P. tricolor Brèthes, 1914, P. joergenseni Brèthes, 1914, P. cleone Brèthes, 1914, P. dorsata Brèthes, 1914, P. aretheas Brèthes, 1914, P. lassonis Lucas, 1819, P. consors Banks, 1946, P. interrupta Banks, 1946, P. analis Haupt, 1952; P. seladonica Dahlbom, 1843 = P. deuteroleuca Smith, 1855, P. kohli Lucas, 1895, P. venezolana Brèthes, 1908, P. burmeisteri Brèthes, 1908; P. cybele Banks, 1945 = P. weberi Banks, 1946; P. thoreyi Dahlbom, 1845 = P. lurida Lucas, 1895, P. euterpe Brèthes, 1908; P. flavescens Lucas, 1895 = P. periphetes Lucas, 1895, P. limbatella Brèthes, 1908, P. discoidalis Brèthes, 1914, P. limbatica Brèthes, 1914, P. militaris Brèthes, 1914, P. cavillatrix Haupt, 1952, P. arcuata Haupt, 1952, P. recterugosa Haupt, 1952, P. adversatrix Haupt, 1952; P. nigricans Lucas, 1895 = P. troglodytes Brèthes, 1908; P. montezuma Smith, 1855 = P. quitonensis Packard, 1869, P. sibylla Mocsáry, 1885, P. circe Mocsáry, 1885, P. occidentalis Cameron, 1893, P. peruanus Lucas, 1895, P. fulva Lucas, 1895, P. nessus Lucas, 1895, P. fusca Lucas, 1895, P. andicola Cameron, 1903, P. chilloensis Cameron, 1903, P. patagonica Brèthes, 1908, P. fasciculata Brèthes, 1908, P. pisoensis Strand, 1911, P. pacifica Brèthes, 1914, P. huascar Banks, 1946; P. completa Smith, 1855 = P. quichua Brèthes, 1908, P. comes Banks, 1946; P. smaragdina Dahlbom, 1843 = P. thunbergi Dahlbom, 1843, P. lara Mocsáry, 1888, P. satrapes Lucas, 1895, P. nupta Lucas, 1895, P. erynnis Lucas, 1895, P. fraterna Lucas, 1895, P. diabolus Lucas, 1895, P. mystica Lucas, 1895, P. thalia Brèthes, 1908, P. brasiliensis Brèthes, 1908, P. pallida Brèthes, 1908, P. iheringi Brèthes, 1908, P. dromeda Brèthes, 1908, P. sepultrix Lucas, 1919, P. strickeri Lucas, 1919; P. discolor Taschenberg, 1869 = P. sinnis Lucas, 1895, P. jujuyensis Brèthes, 1908, P. modesta Brèthes, 1908, P. comparata Brèthes, 1908, P. neutra Brèthes, 1908, P. terebrans Brèthes, 1908, P. procera Haupt, 1952, P. plaumanni Haupt, 1952, P. ogloblini Haupt, 1952, P. deletrix Haupt, 1952; P. limbata Guérin, 1831 = P. richteri Brèthes, 1908, P. polita Brèthes, 1908, P. limbella Haupt, 1952, P. artemis Haupt, 1952; P. basalis Mocsáry, 1885 = P. erdmanni Lucas, 1895, P. basinigra Haupt, 1952; P. infuscata Spinola, 1841 = P. niobe Mocsáry, 1885, P. sagana Mocsáry, 1894, P. incerta Banks, 1946; P. hyalinipennis Mocsáry, 1885 = P. subruficornis Haupt, 1952; P. festiva Fabricius, 1804 = P. pulchella Lepeletier, 1845, P. solitaria Smith, 1879, P. gallardoi Brèthes, 1908, P. hora Brèthes, 1914, P. amok Lucas, 1919, P. riojaneirensis Lucas, 1919; P. gracilis Lepeletier, 1845 = P. diana Mocsáry, 1885, P. hecate Mocsáry, 1885, P. spathulifera Lucas, 1895, P. sphinx Lucas, 1895, P. ierensis Banks, 1945, P. alceste Banks, 1946, P. scalaris Haupt, 1952; P. mildei Stål, 1857 = P. charon Mocsáry, 1885, P. cyanoptera Lucas, 1895, P. dryas Lucas, 1919; P. filiola Brèthes, 1914 = P. denserugosa Haupt, 1952; P. ruficornis Fabricius, 1804 = P. saphirus Palisot de Beauvois, 1805, P. violacea Mocsáry, 1885, P. hexamita Lucas, 1895, P. omniviolacea Haupt, 1952; P. brunneicornis Lucas, 1895 = P. glabripennis Lucas, 1895; P. purpurea Smith, 1873 = P. pan Mocsáry, 1885, P. parthenope Mocsáry, 1885, P. sagax Lucas, 1895, P. clypeata Brèthes, 1914, P. consimilis Banks, 1946, P. laconia Banks, 1946; P. viridisetosa Spinola, 1841 = P. eximia Smith, 1873; P. viridis Lepeletier, 1845 = P. errans Lepeletier, 1845, P. chlorotica Mocsáry, 1885, P. excelsa Lucas, 1895, P. selene Lucas, 1895, P. fimbriata Lucas, 1895, P. calypso Brèthes, 1908, P. fluminensis Brèthes, 1908, P. argentinicus Strand, 1910, P. mimetica Brèthes, 1914, P. garbei Brèthes, 1914, P. erecta Brèthes, 1914, P. tandilensis Brèthes, 1914, P. meridionalis Brèthes, 1914, P. minor Lucas, 1919, P. basifulgens Lucas, 1919, P. nebulosipennis Lucas, 1919, P. purpurea Lucas, 1919, P. koerberi Lucas, 1919, P. inimicissima Lucas, 1919, P. debilitans Lucas, 1919, P. itapaca Banks, 1946; P. aciculata Taschenberg, 1869 = P. nero Lucas, 1895; P. atripennis Fabricius, 1804 = P. flavilis Brèthes, 1908; P. ianthina Erichson, 1848 = P. fulvicornis Mocsáry, 1885, P. sirene Lucas, 1895, P. balboae Lucas, 1919, P. herodes Lucas, 1919, P. curti Lucas, 1919; P. nana Mocsáry, 1885 = P. mapiriensis Lucas, 1919, P. vinciens Lucas, 1919, P. ilione Banks, 1946, P. moesta Banks, 1946, P. orestes Banks, 1946, P. amautas Banks, 1946, P. inaequalis Haupt, 1952; P. hirtiventris Banks, 1946 = P. viridaurea Haupt, 1952, P. aequalis Haupt, 1952; P. auriguttata Burmeister, 1872 = P. aurimacula Mocsáry, 1885, P. flavicornis Mocsáry, 1894, P. guttata Lucas, 1895, P. incendiaria Lucas, 1895, P. pubiventris Lucas, 1895, P. planifrons Lucas, 1895, P. lestes Lucas, 1895, P. villosa Brèthes, 1908; P. sabina Mocsáry, 1885 = P. astioles Banks, 1946; and P. purpureipes Packard, 1869 = P. chlorana Mocsáry, 1885, P. antennalis Cameron, 1893, P. sulcifrons Cameron, 1903, P. carinata Brèthes, 1914, P. equatoriana Brèthes, 1914, P. angusta Banks, 1946. Keys to all forms are given. The mimicry-groups of P. atripennis Fabricius, 1804, and P. completa Smith, 1855, are defined and described and a comparative account of mimicry based on all four mimicrygroups in Pepsis is given. Lists of excluded species (with their current taxonomic placement and depository where ascertained), unplaced names, and a nomen nudum are given.
Spider wasps, i.e., the family Pompilidae, in general, and those belonging to the genus Pepsis in particular, are acknowledged to possess venoms that are algogenic to humans and thus have the parsimonious functions of causing paralysis and providing defense against predators. The morphological organization of the venom system and its complex convoluted gland closely resembles that in social members of the Vespidae. These features distinguish the venom glands of the Pompilidae from those of the sibling family Mutillidae as well as those of the family Sphecidae, which lack convoluted glands. Although the venom glands in Pepsis species are very similar in morphology to those of social vespids, the lethality of Pepsis venom to mammals is several times less than that of the social common wasps. These findings suggest that in terms of the evolution of venom activity and the associated glandular structures, there was apparently no need for social wasps to develop extra parts of the venom system for producing toxic, lethal, or powerful algogenic components. All of the glandular parts of the venom gland of social wasps were already present in pompilids (and eumenids) and, presumably, in their ancestors.
In this study we investigated the ability of females of the spider wasp, Pepsis thisbe, to detect and respond to chemosensory cues associated with two species of theraphosid hosts (Aphonopelma moderatum and A. texense), as well as a novel chemical cue associated with a stored grain beetle (Tribolium confusum), a species not likely to be encountered by these wasps. Field-collected adult wasps were subjected to choice experiments
where they were exposed to a piece of filter paper conditioned with one of these treatment cues versus one sprayed with water
(control). One half of the floor of a test chamber contained the treatment cue, while the other contained the control paper.
For each trial, the amount of time spent on each paper was recorded. Wasps spent significantly more time on paper conditioned
with chemical cues associated with A. moderatum than they did on paper conditioned with cues from A. texense or T. confusum. In addition, field data collected at the study site in southern Texas (Zapata County), showed that over 91.2% of all P. thisbe larvae were found attached to A. moderatum as compared to only 8% for A. texense, despite the fact that the abundance and size of these two theraphosids were similar. Eighty-one percent of all paralyzed
A. moderatum found with wasp larvae attached to their bodies were females.
The effect of 19 venoms from solitary wasps, solitary bees, social wasps and ants were investigated for their effects on nicotinic acetylcholine receptors (nAChR) and ionotropic glutamate receptors (IGRs) of both the N-methyl-d-aspartate (NMDAR) and non-NMDAR type. Whole-cell patch clamp of human muscle TE671 cells was used to study nAChR, and of rat cortical and cerebellar granule cells for IGRs. Solitary wasp venoms caused significant voltage-dependent antagonism of nAChR responses to 10 microM ACh and NMDAR responses to 100 microM NMDA (+10 microM glycine) when co-applied at 1 microg/ml with the agonists. At positive holding potentials (V(H)) potentiation of these receptors was observed with some venoms. Solitary bee venoms only affected nAChR by causing either voltage-independent antagonism or potentiation of their responses to 10 microM ACh. Of four social wasp venoms, one acted on nAChR by potentiating responses to 10 ACh, while another generated an ACh-like response when applied alone. They had no effect on IGRs. Of the two ant venoms, one caused voltage-independent inhibition of nAChR. Neither affected IGRs. The data indicate the presence of nAChR agonists and antagonists and NMDAR antagonists in Hymenopteran venoms and warrant further investigation to separate and identify these venom components.
Acoustic signals produced by caterpillars have been documented for over 100 years, but in the majority of cases their significance is unknown. This study is the first to experimentally examine the phenomenon of audible sound production in larval Lepidoptera, focusing on a common silkmoth caterpillar, Antheraea polyphemus (Saturniidae). Larvae produce airborne sounds, resembling ;clicks', with their mandibles. Larvae typically signal multiple times in quick succession, producing trains that last over 1 min and include 50-55 clicks. Individual clicks within a train are on average 24.7 ms in duration, often consisting of multiple components. Clicks are audible in a quiet room, measuring 58.1-78.8 dB peSPL at 10 cm. They exhibit a broadband frequency that extends into the ultrasound spectrum, with most energy between 8 and 18 kHz. Our hypothesis that clicks function as acoustic aposematic signals, was supported by several lines of evidence. Experiments with forceps and domestic chicks correlated sound production with attack, and an increase in attack rate was positively correlated with the number of signals produced. In addition, sound production typically preceded or accompanied defensive regurgitation. Bioassays with invertebrates (ants) and vertebrates (mice) revealed that the regurgitant is deterrent to would-be predators. Comparative evidence revealed that other Bombycoidea species, including Actias luna (Saturniidae) and Manduca sexta (Sphingidae), also produce airborne sounds upon attack, and that these sounds precede regurgitation. The prevalence and adaptive significance of warning sounds in caterpillars is discussed.
The lethality to mice of the venoms from 7 species of ants, 7 species of wasps in the family Vespidae, 2 species of bees, and 1 species of solitary parasitic wasp are reported for the first time. The LD50 (24 hr) values ranged between a low of 0·25 mg/kg and a high of 71 mg/kg. Although venoms from congeneric species exhibited similar lethalities, no correlations between venom lethality and higher taxonomic groupings were evident. The results of this study reemphasise the fact that hymenopterous venoms are characterized more by their differences than by their similarities.
Aspects of the natural history and behavioral ecology of the spider
wasp, Pepsis thisbe were studied in Trans Pecos, Texas with
special emphasis on larval development and host interactions.
Additional parameters studied include the physical dimensions of
the egg, larval and adult size, fecundity, egg survivorship and duration
of embryonic and postembryonic development as a function of
temperature and relative humidity (RH), larval growth and behavior,
the relationship between adult wasp and host sizes, and ontogenetic
changes in larval feeding patterns. Eggs and larvae did not
survive when exposed to xeric conditions (10% RH). Forty-one
days were required to progress from egg to emerged adult at 3℃
and 70% RH.
The temporal pattern of activity and hunting behavior of the spider
wasp, Pepsis thisbe, from Trans Pecos, Texas are described.
Females exhibited a bimodal pattern with peak periods of hunting
activities occurring between 0800–0959 and 1600–1759 hr. The
lowest levels of activity (1100–1359 hr) occurred when ambient
temperatures exceeded 38℃. Activity declined abruptly after 1800
hr indicating a strong preference for diurnal activity in this species.
The behavioral components of the hunting sequence consist of an
initial approach and antennation of the host, grooming, antennation
and paralyzation followed in some cases by lapping, ovipositiom
burial of the host, and closure of the nest. The time required to
complete the hunting sequence was recorded for both field and laboratory
encounters between a wasp and spider. The amount of time
required by a female wasp to complete the initial approach and
antennation-paralyzation sequences decreased significantly as a
function of increasing encounter experience. The spider is stung
most frequently (>80%) through the intersegmental membrane
between the sternum and coxa of the first leg. Whether or not a
wasp exhibits lapping behavior is determined by the amount of
time spent in flight searching for a host burrow.
Spider wasps, i.e., the family Pompilidae, in general, and those belonging to the genus Pepsis in particular, are acknowledged to possess venoms that are algogenic to humans and thus have the parsimonious functions of causing paralysis and providing defense against predators. The morphological organization of the venom system and its complex convoluted gland closely resembles that in social members of the Vespidae. These features distinguish the venom glands of the Pompilidae from those of the sibling family Mutillidae as well as those of the family Sphecidae, which lack convoluted glands. Although the venom glands in Pepsis species are very similar in morphology to those of social vespids, the lethality of Pepsis venom to mammals is several times less than that of the social common wasps. These findings suggest that in terms of the evolution of venom activity and the associated glandular structures, there was apparently no need for social wasps to develop extra parts of the venom system for producing toxic, lethal, or powerful algogenic components. All of the glandular parts of the venom gland of social wasps were already present in pompilids (and eumenids) and, presumably, in their ancestors.
Wasps of the genera Pepsis and Hemipepsis are our largest hymenoptera. A large Pepsis is about an inch and a half long; the tarantulas, their common prey and provision for the young of these wasps, are our largest spiders. Encounters between “tarantula hawks, as these big wasps are frequently called, and tarantulas have often been observed and occasionally recorded in literature. But there has not been much information on what species of wasp attacks what species of tarantula, nor on some of the aboveground operations subsequent to these encounters. This paper supplies some of these data, and partly fills in the almost complete void hitherto existing on the early stages of these pepsine wasps, as well as the operations of the mother wasp in the dark underground where she prepares the way for her offspring that she will never see.
Gregarious “sleeping is characteristic of many species of wasps and bees and the behavior involved is sufficiently consistent to suggest that it is basically instinctive. It may be limited primarily to individuals of the same species, or may involve individuals of two or more species. Single-species “sleeping aggregations may be maintained as separate units which retain their identity without adopting a regular “sleeping site (e.g., Sphex lucae), or reassemble on successive nights at a “sleeping site shared with other species (e.g., Priononyx pubidorsnin, Anthidiellum notatum robertsoni). Individuals that share the same sleeping site exhibit varying degrees of tolerance toward others of the same or different species, and -thus varying degrees of gregariousness. The characteristics of “sleeping plants utilized by successive generations of wasps and bees may vary, suggesting that the choice may be made by the first users, the others following. A preference is suggested for dead or dry, relatively rigid, moderate-sized (3-6-ft.-tall), multibranched plants with numerous upright or nearly vertical stems of suitable diameter, an exposure to the morning and evening sun, and a certain amount of wind-protection provided by denser plants or other objects. At low population levels, sleeping sites for certain species within the plant appear to be consistent from season to season and from “sleeping plant to “sleeping plant. In other cases the choice appears to be fortuitous and varies from season to season and plant to plant. In either event, learning appears to be a factor for many, some individuals returning to the same section of the plant each night, others to the same roost. At high population levels the basic pattern of some of the otherwise consistent species may be modified, and vary from night to night. At low population levels a gradual modification of established patterns may be evident as the season progresses. The sequence of arrival, settling, sleeping, and departure of several of the “regular members of “sleeping aggregations is sufficiently consistent to suggest that these reactions may be inherited. Regular members of sleeping aggregations usually involve both sexes of “parasitic bees, other nonnesting species, and species which do not have nests in the ground or in some other substrate. Irregular and casual members include males of many species and females of a variety of nesting habits. Species which “sleep individually, even though individuals may sometimes be arranged in small groups, tend to assume a regular sleeping posture which is constant from individual to individual and from night to night (e.g., Ammophila spp., Anthidiellum n. robertsoni). Those which tend to cluster within the aggregation, either loosely or tightly, do not assume regular postures, either when sleeping gregariously or singly (e.g., Priononyx pnbidorsum, Sphex lucae). The consistency of sleeping patterns exhibited by several species and the uniformity of sleeping position adopted by individuals suggest that each has a selective value, the nature of which requires further study.
Using column chromatography, a protein, selectively toxic to isopods (Crustacea) has been isolated and purified from the venom of the scorpion Androctonus australis. The final product is about 250 times more toxic than the crude venom. It is a low molecular weight (70 amino acids) basic protein, devoid of methionine, histidine, and phenylalanine, rich in arginine and supposed to contain five disulfide bridges.The amino acid composition of this toxin is compared to those specifically active to mammals as well as to insects derived from the same venom, and the significance of such selectivity in action is discussed.
Pure neurotoxins separated from the venom of the scorpion Androctonus australis Hector and highly toxic to mammals are inactive when tested on several arthropods. The fly larvae toxin originating from the same venom demonstrates a strong toxicity to insects but is completely inactive when applied to an arachnid or a crustacean. Recycling gel filtration, on Sephadex G-50, of the crude venom allows the isolation of a product exhibiting a high paralyzing and lethal activity to a crustacean. The toxic activity is destroyed by trypsin digestion. It is concluded that, in addition to the toxins active in mammals and insects, the venom of A. australis contains another discrete protein specifically active on a crustacean.
Crude black widow spider venom (BWSV) has profound physiological effects on several neuromuscular preparations, both vertebrate and invertebrate1. At frog and mouse neuromuscular junctions (NMJs), BWSV causes a massive increase in the frequency of miniature endplate potentials (m.e.p.ps)2,3 followed by a reduction in m.e.p.p. frequency and depletion of synaptic vesicles3-5. Qualitatively similar physiological and morphological effects are also observed at lobster6-8 and insect9,10 NMJs after treatment with BWSV. Apparently, therefore, this venom can cause the release of several transmitters-acetylcholine at vertebrate NMJs and gamma-aminobutyric acid (GABA) and glutamate at invertebrate NMJs11. BWSV has also been shown to cause the release of acetylcholine, noradrenaline and GABA from slices of mouse cerebral cortex12,13. alpha-Latrotoxin, a protein of molecular weight (MW) 130,000, had previously been shown to be responsible for the venom effects at vertebrate NMJs and in mouse brain slices12-14. That finding prompted the question of whether alpha-latrotoxin was also responsible for transmitter release in the lobster preparation. The present report demonstrates that although the electrophysicological effects of BWSV on lobster and frog NMJs are similar, they are caused by different components of the venom. The effects on the lobster are attributable to fraction E, which contains a major 65,000-MW protein and several lower molecular weight species. It has previously been shown that fraction E causes firing of the crayfish stretch receptor14. Some of these results have been published elsewhere15.
The venoms of Apis dorsata, A. cerana, A. florea, and three different populations of A. mellifera were compared for lethal activity toward mice. All venoms exhibited identical activities, a finding consistent with recent evolutionary history within the genus. Young queen honeybees use their venoms only for stinging other queens and possess a venom only half as lethal to mice as worker venom, and by the time queens are 1-2 years of age their venom has become essentially inactive. Phospholipase A2 is the most lethal of the honeybee venom peptides, whereas melittin, which is only slightly less lethal, is the most abundant. Concurrent analyses of melittin, phospholipase, and the combination of the two at their natural 3:1 mixture in bee venom revealed that the lethal activity of the mixture was about the same as native honeybee venom. This value was less than that for either melittin or phospholipase alone and indicates that synergism of the two peptides is not occurring. The results are consistent with independent lethal activities for the venom components, and show that melittin is not only the dominant, but also the main lethal component in honeybee venom.
Wasp Farm
- H E Evans
Evans, H. E. 1973.. Wasp Farm. University of Michigan Press, Ann Arbor, Michigan. vii + 188 pp.
Notes on a sleeping aggregation of solitary bees and wasps
- H E Evans
- E G Linsley
Evans, H. E. and E. G. Linsley. 1960.. Notes on a sleeping aggregation of solitary bees and wasps. Bulletin of the Southern California Academy of Sciences 59: 30-37..
The Wasps
- H E Evans
- M J West
Evans, H. E. and M. J. West-Eberhard. 1970.. The Wasps. University of Michigan Press, Ann Arbor, Michigan. vi + 265 pp.
Wasp Studies Afield
- P Rau
- N Rau
Rau, P. and N. Rau. 1918.. Wasp Studies Afield. Princeton Univ. Press, Princeton, New Jersey (1970 Edition, Dover Publ. Inc., New York. xi + 372 pp.).
Association of Mydas xanthopterus (Loew) (Diptera: Mydidae) and Pepsis formosa Say (Hymenoptera: Pompilidae) in the Chiricahua Mountains of Southeastern Arizona
- R P Meyer
- T L Mckenzie
- F G Zalom
Meyer, R. P., T. L. McKenzie, and F. G. Zalom. 1984. Association of Mydas xanthopterus (Loew) (Diptera: Mydidae) and Pepsis formosa Say (Hymenoptera: Pompilidae) in the Chiricahua Mountains of Southeastern Arizona. Pan-Pacific Entomologist 60:357.
Dasymutilla occidentalis: a long-lived aposematic wasp (Hymenoptera: Mutillidae)
- J O Schmidt
Schmidt, J. O. 1978. Dasymutilla occidentalis: a long-lived aposematic wasp (Hymenoptera: Mutillidae).
Ecological notes on male Mydas xanthopterus (Loew) (Diptera: Mydidae) and their interactions with Hemipepsis ustulata Dahlbohm (Hymenoptera: Pompilidae)
- J W Nelson
Nelson, J. W. 1986. Ecological notes on male Mydas xanthopterus (Loew) (Diptera: Mydidae) and their interactions with Hemipepsis ustulata Dahlbohm (Hymenoptera: Pompilidae). Pan-Pacific Entomologist 62:316–322.
Revision of the Nearctic species of the pompilid genus Pepsis (Hymenoptera, Pompilidae)
- P D Hurd
- Jr
Hurd, P. D., Jr. 1952. Revision of the Nearctic species of the pompilid genus Pepsis (Hymenoptera, Pompilidae). Bulletin of the American Museum of Natural History 98:260–334.
Asilidae Wyliea mydas (Brauer) Large, orange wings Coleoptera: Cerambycidae Tragidion deceptum Hovore and Giesbert* Coloration/flight like Pepsis: C. A. Olson, pers
- Diptera
Diptera: Asilidae Wyliea mydas (Brauer) Large, orange wings Coleoptera: Cerambycidae Tragidion deceptum Hovore and Giesbert* Coloration/flight like Pepsis: C. A. Olson, pers. comm.;