In addition to caste polyphenism in social insects, aphids display one of the widest ranges of polyphenism, which produces several distinct phenotypes in response to environmental stimuli, e.g., daylength and density conditions. However, the mechanisms underlying aphid polyphenism remain poorly understood. This study was designed to evaluate the developmental impact of density conditions. We compared the morphologies of winged and wingless parthenogenetic females in the aphids Acyrthosiphon pisum and Megoura crassicauda, based on body-part measurements and observations by scanning electron microscopy. The earliest and the most remarkable differences between winged and wingless morphs appeared in the mesothoracic parts from the third instar, where wings are formed in the winged morphs. Winged adults also have narrower heads, well-developed compound eyes and well-sclerotized thoracic cuticles, compared with wingless adults. Although differences in hind-tibia length were identified in both species, the relationships between the two morphs were reversed in the two species, probably because the ecological significances of the winged/wingless morphs are different between the two species.
Chemical signals causing attraction and alarm in four European subterranean termite species of the genus Reticulitermes (R. santonensis, R. lucifugus, R. grassei, R. banyulensis) were investigated. Natural extracts and isolated compounds from workers and soldiers were offered as odor source in a petri dish to groups of termites, and their behavioral reaction was registered. Pentane extracts of whole workers were attractive, and in three of the species induced a slight alarm reaction. The extracts contained 3-octanone, 3-octanol, and six fatty acids (C14-C18), presumably originating from the cuticle. Species-specific differences were quantitative. When tested individually or as synthetic mixture the worker compounds were significantly less effective than the natural extract. Only the ketone, the alcohol, and one of the fatty acids had any effect, functioning predominantly as attractants. Reticulitermes soldiers possess a frontal gland, which is employed for chemical defense of the colony, and contains species-specific mixtures of terpenes: monoterpenes, sesquiterpenes, diterpene alcohols, and a sesterterpene. All compounds of the frontal gland secretions proved to be highly attractive to the respective species, acting significantly stronger than worker compounds. The minor volatile compounds, the mono- and sesquiterpenes, function as alarm pheromone in Reticulitermes: they were the most attractive components, and also the ones inducing an intense alarm reaction in both workers and soldiers.
Whether or not termites initiate damage to timber via the end grain may determine the need for spot-treating the exposed untreated cut ends of envelope-treated softwood framing material. Australian Coptotermes acinaciformis (Froggatt) were field-tested for their ability to initiate feeding via the end grain of timber (35 × 90 mm) treated with a repellent Tanalith® T envelope. Specimens of commercial radiata pine Pinus radiata D.Don framing timber (untreated) and slash pine Pinus elliottii Englem. (untreated and envelope-treated) were partially clad in fine stainless steel mesh. Clad and unclad specimens were exposed to C. acinaciformis near Townsville, North Queensland, Australia, for four months. Results showed that this species of termite can indeed damage timber via the end grain, including exposed untreated cut ends of envelope-treated material as demonstrated earlier for different populations of C. acinaciformis. Differences between the test conditions in field trials carried out at different times (where C. acinaciformis either did or did not damage timber via the end grain) are discussed. Clearly, outcomes from field studies with preservative-treated materials are dependent upon experimental conditions. Notably, the amount of bait wood (highly termite-susceptible timber substrate) offered in a given method can strongly influence the termite response. Further investigation is required to standardise this aspect of conditions in protocols for the assessment of wood preservatives.
Seven termite species (Isoptera) from five families were tested for disease susceptibility against the entomopathogenic fungus Metarhizium anisopliae using a standard protocol: Mastotermes darwiniensis (Mastotermitidae), Hodotermopsis sjoestedti (Termopsidae), Hodotermes mossambicus (Hodotermitidae), Kalotermes flavicollis (Kalotermitidae), Reticulitermes flavipes and Prorhinotermes canalifrons (Rhinotermitidae), and Nasutitermes voeltzkowi (Termitidae). Our results showed a large diversity in disease susceptibility against M. anisopliae among the different species tested and we suggest that the evolution of disease resistance mechanisms in Isoptera may be influenced by the selective pressure of the nesting ecology of each species.
Individual mound characteristics of Solenopsis richteri Forel, the black imported fire ant, were studied for one year in northern Mississippi pastures. Mounds were largest in May and smallest in November (41.5 ± 4.7 and 26.2 ± 4.1 L, respectively). Vegetation cover (vegetation growing from the mound surface) was greatest in August (75.8 ± 3.8 %) and lowest in November (34.1 ± 3.7 %); vegetation cover was about 30% greater on inactive (= abandoned) mounds than active mounds in February and May, but statistically similar in August and November. The proportion of mounds that were active ranged from 68 to 75%. Mounds were more eccentric during cooler months than during the summer. Seasonal changes in mound characteristics are discussed in light of their possible effects on mound detection using remote sensing techniques.
We report herein detailed morphological differences between sexes in the ponerine ant Diacamma sp. The female individuals of this species show monomorphism, making them particularly suitable among the social hymenopterans for comparing adult sexual traits and developmental processes. Our observations revealed some intriguing sex-specific characteristics. For example, antennal sensilla are gender-specialized in these ants; males possess sensilla coeloconica, thought to respond to air conditions, while females possess a particular type of sensilla basiconica that is a putative contact chemoreceptor. The antennal cleaners in the foretibiae of the legs are also sex-specific, in addition to the trichome patterns on the spurs in the mid- and hind tibiae. Furthermore, only male tarsal claws have a denticle inside the claw, and the male posterior abdomen has a hook-like curved spine at the edge of the eighth tergite. This spine is thought to facilitate the tight connection of a mating pair. Based on these findings, we hypothesized that most of the sexually dimorphic traits are morphologically specialized for and thus function in the different gender life strategies, such as flight ability, lifespan, and male suicidal copulation.
In social insects, caste morphologies are different depending on their tasks allocated in their colonies. Although many ant species generally possess two female castes: winged queen and wingless worker, in some Myrmecina species, some colonies produce a wingless reproductive caste instead of alate queens. This wingless reproductive caste is termed 'intermorphic' queen, and its morphological features are intermediate between winged queen and worker. In the present study, we analyzed the morphological features of the three female castes to explore the adaptive meaning of the intermorphics in terms of reproductive strategy, in addition to the developmental and evolutionary origin in Myrmecina nipponica. We first performed the principal component analysis based on the morphometric data of the three female castes of adults (alate queen, intermorphic queen and worker). The results of analysis showed that allometry of the intermorphic queen differ from those of alate queen and worker. In intermorphics, compound eyes and gasters were more developed in comparison with heads and thoraxes. We also examined several body parts in detail by scanning electron microscopy in the three female castes. The morphological features of intermorphics varied widely compared with the other two castes. Intriguingly, some parts of intermorphics were queen-like, while others were worker-like. Our findings suggest that the morphological features of intermorphic queens have specialized reproductive strategy involving budding.
The little fire ant, Wasmannia auropunctata, has been increasing in importance as an exotic pest. Here we review published and unpublished information on its distribution, ecology, impact, and control. Wasmannia auropunctata occurs throughout most of the warmer parts of the New World, from subtropical Argentina to subtropical Mexico and through much of the Caribbean, though it is not clear whether this species is native to this entire region. During the past century, exotic populations of W. auropunctata have become established in numerous other places, including the Galapagos Islands, West Africa (Gabon, Cameroon, and possibly the Republic of Congo and the Democratic Republic of Congo), Melanesia (New Caledonia, Solomon Islands, Vanuatu, and possibly Tuvalu), Polynesia (Wallis and Futuna and Hawaii), the mainland US (Florida and possibly California), and on subtropical Atlantic islands (the Bahamas and Bermuda). The latitudinal range of known outdoors populations of W. auropunctata is from 32o40'S in Argentina to 32o20'N in Bermuda. Wasmannia auropunctata is also a greenhouse pest in more temperate regions, such as England and Canada. In many areas, W. auropunctata can be a significant agricultural pest, not only stinging agricultural workers, but also enhancing populations of Homoptera. Homoptera cause damage both through sapping plants of nutrients and by increasing the occurrence of diseases, including viral and fungal infections. In addition, W. auropunctata has negative impacts on many animals, both invertebrates and vertebrates, though most reports on such impact have been anecdotal. The impacts of W. auropunctata populations seem to be most severe on tropical islands where it is not native, such as the Galapagos, New Caledonia, and the Solomon Islands. Reports of widespread blindness in both domestic and native mammals caused by W. auropunctata stings deserve serious attention. Chemical control of W. auropunctata may be possible for small exotic populations spread over a few dozen hectares or less. For large exotic infestations, the only hope for long-term control appears to be classical biocontrol.
Monthly abundance and caste proportions of subterranean termites (Reticulitermes spp.) inhabiting red imported fire ant (Solenopsis invicta Buren) mounds were recorded during 1999 and 2000 from a relatively undisturbed forest edge in Tuskegee, Alabama. Temperature data were also recorded at these mounds; mean air, soil, and mound temperatures followed a sine model over the course of the year. During the late fall and early winter, relative proportion of young workers (< 3rd instar) increased from 0 to 66.7% of the sample from the previous month, suggesting a change in temperature requirements among termite castes. These data demonstrate that Reticulitermes spp. termites are found year-round inhabiting active fire ant mounds, although relative caste proportions change seasonally. The hypothesis of a minimum soil temperature determining the movement of young Reticulitermes spp. workers into fire ant mounds (or other locations of increased temperature) is discussed.
Traditional measures of termite food preference assess consequences of foraging behavior such as wood consumption, aggregation and/or termite survivorship. Although studies have been done to investigate the specifics of foraging behavior this is not generally integrated into choice assay experiments. Here choice assays were conducted with small isolated (orphaned) groups of workers and compared with choice assays involving foragers from whole nests (non-orphaned) in the laboratory. Aggregation to two different wood types was used as a measure of preference. Specific worker caste and instars participating in initial exploration were compared between assay methods, with samples of termites taken from nest carton material and sites where termites were feeding. Aggregation results differ between choice assay techniques. Castes and instars responsible for initial exploration, as determined in whole nest trials, were not commonly found exploring in isolated group trials, nor were they numerous in termites taken from active feeding sites. Consequently the use of small groups of M. turneri worker termites extracted from active feeding sites may not be appropriate for use in choice assays.
The highly persistent cyclodiene (organochlorine) insecticides (aldrin, dieldrin, chlordane and heptachlor), the main termiticides used in Australia for 30 years, were withdrawn from use in most of Australia on 30 June 1995. Alternative strategies for subterranean termite management in buildings and other structures had been under development, well before this withdrawal. Here we focus on these and subsequent developments in subterranean termite management, relevant to Queensland, including a national survey, relevant building regulations, approvals and changes in the Australian Standards on termite management. Developments including a national training and competency-based-licensing system for pest managers, insurance of dwellings against termite damage and several alternative termite management strategies are discussed. An integrated approach to termite management is the likely direction for the future in Australia, minimising reliance on chemical sprays and drenches. There will be an increased need for physical barriers in improved building design and reliable preventative and remedial treatments involving bait technology. The need for research on termite biology and, in particular, foraging behavior is emphasized yet again.
Hydroquinone is a phagostimulating pheromone found in labial glands of most, if not all, termite species. In this study, we investigated whether hydroquinone enhances the effectiveness of bait systems for termite control. Laboratory feeding choice tests on filter paper with Mastotermes darwiniensis Froggatt and Coptotermes acinaciformis (Froggatt) demonstrated that several compounds chemically related to hydroquinone had a phagostimulating effect, but none as strong as the natural pheromone. Hydroquinone also works as short-distance attractant: termites were lured towards a source of hydroquinone over a distance of several centimeters. In long-term laboratory choice feeding tests, M. darwintensis and C. acinaciformis consumed significantly more wood within three days and one week, respectively, if hydroquinone had been applied. The preference had diminished after four weeks. Addition of glucose or amino acids did not increase the phagostimulating effect of hydroquinone. In field tests, hydroquinone proved to be comparatively stable under natural conditions: after four weeks in the soil, ca. 30% of the original amount of hydroquinone was still left in the baits. In field baiting trials with colonies of M. darwiniensis, C. acinaciformis, and C. lacteus in Australia, hydroquinone significantly increased feeding and the number of termites in treated baits compared to controls. Preliminary field trials with 10 further termite species in Australia and overseas confirmed these results.
Effects of three particle film products on Formosan subterranean termites, Coptotermes formosanus Shiraki, were evaluated in feeding, tunneling, and contact assays. The particle films, hydrophobic M96-018 and hydrophilic Surround and Surround WP are based on the inert clay mineral kaolin. In 2-week long no-choice feeding tests, significant mortality occurred only with M96-018-coated wood. When a choice was provided, M96-018 and Surround were consumed at higher rates than untreated wood. Surround WP did not differ from controls in either test. In the tunneling assay termites were given the option of crossing a kaolin-sand mixture to reach an alternate food source. After 3-weeks, rates of 1% and 5% M96-018 provided an effective barrier to Formosan termite tunneling, while termites were not stopped by rates as high as 20% Surround and Surround WP. Dust treatments of all three formulations caused significant increases in mortality within 24 h, with mortality rates ranging from 72.0 - 97.3% within 72 h of treatment. The particle films were most effective when moisture levels were low, suggesting that desiccation was the mechanism for mortality. All particle films showed potential for use in above ground applications while hydrophobic M06-018 has the most potential as a soil barrier to subterranean termites.
Primary reproductives or alates of the Formosan subterranean termite, Coptotermes formosanus, swarm from April-June in Louisiana. About 1200 pairs were set up during 1999 and 2000 using agar and birch sawdust medium. Mating was observed and recorded. The tail to tail mating lasted an average of 28 seconds. Over 400 of these pairs were observed for egg laying, egg hatch and incipient colony development. Four discrete oviposition cycles with intervening periods of rest were observed over a period of two years. Average number of eggs in the first batch was 39. Both ovaries and testes increased in size with age. After an initial slow growth total progeny increased over fivefold towards the end of the second year. Multiple matings were essential to obtain maximum reproductive potential. Removal of the progeny during active egg laying induced increased oviposition. Understanding the reproductive biology of the Formosan subterranean termite is a key to the development of novel approaches for management of this pest.
The foraging process of location and exploitation of food in complex termite societies is in part reliant upon unequal division of specific tasks amongst its members (polyethism). To conduct studies assessing the role of individuals in foraging activities it is necessary to have descriptors of worker caste and instar. Here we provide biometric descriptors of specific caste and instar for worker caste and instars of Microcerotermes turneri (Froggatt) (Termitidae: Termitinae) for the worker castes (male and female) for the identification of individuals in laboratory assays applicable across multiple nests. The use of head width for determining sex of workers was successful across multiple nests. The length of the first three flagellum segments of the antenna and tibia three could be used to determine worker instar.
This report provides new evidence that the spread of C. formosanus in Mississippi is also attributed to commercial activities with some non-wood carriers moved from infested coastal areas. Sequencing of mitochondrial cytochrome oxidase subunit II indicated that the genotype of a termite colony collected from a boat located in south Mississippi, (originally purchased in New Orleans, Louisiana by the owner) has not been previously documented in the southeastern mainland of the United States. Preliminary sequence alignment analysis exhibited that this termite sample from Mississippi was genetically more similar to colonies documented in southeastern Asia.
Regulation of caste systems in the Formosan subterranean termite, Coptotermes formosanus, as in other species of termites, is controlled by external factors such as nutrition and internal factors including age and hormone(s). Here we report primarily on soldier formation. The role of various such factors in regulating pre-soldier formation was examined. Removal of existing soldiers resulted in additional pre-soldier formation. Better nutrition among workers contributed to higher pre-soldier formation. Among regulator hormones, juvenile hormone (JH) is known to play a key role in soldier formation. Newly molted workers were competent to form pre-soldiers if treated with JH. Methoprene, a JH analog induced soldier formation in workers up to a maximum of 40 percent indicating the possibility of an inhibitory feedback signal from existing soldiers. Workers had to be in direct physical contact with pre-soldiers or soldiers to cause the inhibition. Corpora allata, that produced JH, were larger in size in the pre-soldiers as compared to workers and soldiers.
Termites are one of the major groups of social insects, which comprise alates, workers (pseudergates), and soldiers within a species. These castes have different roles and behaviors, and undertake division of labor to increase the inclusive fitness of their colony. On the basis of the different behavioral repertoires, caste-specific neural modifications are predicted, such as modification of sensory systems, i.e., inputs into the nervous system. This study evaluated these sensory-system differences based on mechanoreceptive sensilla length among castes of the damp-wood termite Hodotermopsis sjostedti. We found that soldiers and alates had longer sensilla than pseudergates, and that this variation among castes differed with body region. Specifically, the differences were particularly conspicuous on head capsules and pronota, while sensilla on mouthparts and legs were of similar lengths among castes. It is proposed that soldiers and alates use these long mechanoreceptive structures to sense faint vibrations, an important capability for their defensive role in detecting enemies and cracks in nest wood.
We use an agent-based model to simulate the expression of recognition behavior in the form of aggression among individual workers within colonies of subterranean termites. Inter- and intraspecific recognition in the form of overt aggression varies in the genus Reticulitermes. Three patterns have emerged from nestmate recognition studies in termites: 1) interspecific aggression is often stronger and more immediate than intraspecific aggression, 2) a loss of genetic diversity may result in a loss of aggression, 3) with laboratory bioassays, single individuals don't show overt aggression, whereas groups do. We create an agent-based model that simulates these patterns to understand the mechanisms that create them. We assume that there are three components to successful recognition of alien individuals: the variation in recognition cues among different colonies, signaling among individuals in the same colony, and variation in response thresholds of individuals within the same colony. The results suggest that if cue difference is not significantly variable, and response thresholds are high, aggressive behavior will not be expressed. Under these situations, social signaling becomes increasingly important. The model provides a simple mechanistic description of how aggressive behavior emerges from simple worker-to-worker interactions, and explains a possible reason for a group effect in laboratory bioassays.
Photosensitivity of the Formosan subterranean termite, Coptotermes formosanus Shiraki, was tested in workers, pre-soldiers, and soldiers of various ages. Responses leading to possible foraging behaviors under laboratory bioassay conditions were also determined in response to various light intensities. Whereas workers and pre-soldiers avoid light of all intensities, soldiers while avoiding the light attain a defensive posture by lining up their heads pointing toward the edge of the light source. The tunneling assay further showed that subterranean termites avoid light, and foraging in exposed areas is facilitated by the construction of an opaque mud screen.
The Formosan subterranean termite (FST), Coptotermes formosanus Shiraki, was first introduced to the continental US after WWII. New Orleans' French Quarter (FQ) in particular has been severely impacted experiencing reoccurring cycles of damages and repairs since FST was introduced to the region 65 years ago. Operation Full Stop is a federally funded program established in 1998 by the US Congress. As part of the Operation Full Stop, a project was begun in the FQ to apply area-wide management to suppress the FST population, thereby potentially limiting future damages. To measure the impact of the area-wide program, in-ground stations were placed throughout the FQ to monitor activity of termite foragers. Additionally, alate traps (sticky cards), suspended under street lamps at or near every intersection were use to determine the level of alate activity during the swarm season. An inspection program of structures was initiated in 2003 to determine the percentages of properties with active infestations and to reveal their location for additional treatment. The percentages of active in-ground stations declined to 5% or less depending on the specific FQ neighborhood. Also, since 2006 there has been a 44% to 76% reduction in the number of alates captured, again depending on the neighborhood and how recently it was entered into the program. The inspection program has revealed lingering infestations in some structurally complex facilities. These infestations are problematic for successful area-wide suppression of FST in the FQ. Thus, finding and treating these persistent structural infestations and those in open spaces such as the adjacent levee are necessary for further reduction of FST.
Underground monitoring stations were active with Formosan subterranean termites, Coptotermes formosanus Shiraki, less than a month after City Park, an urban park in New Orleans, Louisiana, was inundated with 0.5 to 2.5 meters of flood water. This study examines whether C. formosanus are able to survive inundation by finding air pockets in either wood or their gallery system in the soil and whether termites move up from the substrate to higher ground in response to rising water. We found no evidence that termites are able to survive in their gallery system or within wood after submersion, and no evidence that termites attempt to move up from the substrate in order to escape rising water. However, significant numbers of termites located within the hollowed-out core of a wood block at the time of the flooding were able to escape slowly rising water. Formosan subterranean termite colonies most likely survived the flooding of City Park because these colonies were living within trees at the time of the flood. The construction of carton nests within the hollowed-out trunks of living trees may be a behavioral adaptation to survive flooding.
Cytochrome P450 monooxygenase activity, using aldrin as a substrate, has been shown to significantly vary between Reticulitermes virginicus (Banks) colonies. Increased monooxygenase activity was accompanied by significantly increased lethal time to mortality when termites were exposed to chlordane. Lethal times to mortality responses were also established for workers and soldiers of the Formosan subterranean termite, Coptotermes formosanus Shiraki, exposed to chlordane and deltamethrin. There were significant differences in the tolerance ratio of workers between colonies. One colony was 16X more tolerant than another to deltamethrin. C. formosanus soldiers also had significant differences in tolerance ratios. A diagnostic dose of deltamethrin did not kill soldiers from one the C. formosanus colonies. Effect of C. formosanus colony tolerance differences on penetration of insecticide treated sand was also investigated.
Carpenter ant colony response (mortality, repellency, and toxicant transfer) to dried fipronil (0.06%) residues was evaluated to determine if ants from different colonies responded to these residues in the same way. Using replications from multiple colonies, a summary LT value was calculated for all carpenter ant colonies confined on fipronil residues (13.9 h). However, tests evaluating the response of individual ant colonies indicated that colonies were not equally susceptible to fipronil (LT50 values ranged 7.4 h-29.3 h). Each of the six colonies evaluated for fipronil susceptibility had LT values that were significantly different from at least four other colonies. Although the differences in susceptibility were observed, fipronil was not found to be repellent to any of the ant colonies tested. When replications from multiple colonies were used to determine fipronil residual activity, statistical analysis indicated that total ant mortality did not decrease even when residues were 6 weeks old. However, when mortality data from the individual colony replicates was averaged, it was found that some colonies in the residual assays experienced very high mean mortality (87%) when exposed to residues (both fresh and aged) and some colonies had very low mean mortality (1%). This variability between the replicates confounded our ability to determine any decrease in fipronil residual activity. Colony foraging activity was quantified and found to be positively correlated to mortality in the residual assays. However, foraging activity was not the ultimate cause of intercolony variability because it did not play a role in the fipronil susceptibility assays. Fipronil horizontal transfer was also documented between carpenter ants. Yet, the percentage of donor ants was not found to be a good predictor of recipient ant mortality when individual replicates were selected from different colonies.
A standard laboratory termite test was conducted in September of 2010 using termites from a single colony of Reticulitermes spp., gathered in East Central Mississippi. Testing was performed adhering to procedures outlined in the AWPA E1-09 Standard termite test. Wood wafers used in the test were treated with an organosilane compound. Observations of worker termites exposed to treated wood wafers during testing included disoriented, convulsive type movements as well as sluggish behavior. Post mortem observations indicated that some worker termites exposed to treated wood wafers assumed a light pinkish to red color, primarily in the head area extending to the abdomen. The abnormal behavior and post mortem color phenomena observed in this test resemble observations in past studies on the association between termites and the bacterium Serratia marcescens.
Decomposition processes in the soil profile (L, F, A1 and A2 layer) in a seasonal tropical forest in Thailand was investigated and compared to the epigeal mound of the soil-feeding termite Dicuspiditermes makhamensis by CP/MAS 13C NMR. The main characteristics of carbon structural changes during decomposition was the loss of carbohydrate and accumulation of recalcitrant aliphatic compounds. In terms of CP/MAS 13C NMR, there is no clear difference between the carbon composition of the termite mound and that of the surface organic soil layer, suggesting that the effect of the soil-feeding termite is not very prominent on soil carbon structure.
Translocation of [14C] fipronil by Reticulitermes flavipes (Kollar) from treated soil to the internal surface of foraging galleries outside of a treated soil zone was investigated. We tested the hypothesis that termites will acquire fipronil from treated soil via contact and passively distribute the toxicant on gallery surfaces by incidental contact during foraging. To test this hypothesis, artificial foraging arenas were constructed that consisted of nest and food chambers connected to a treated soil chamber by polyethylene tubing. Treated soil chambers contained 1, 4, or 8 ppm [14C] fipronil treated soil. Groups of 150, 300, or 600 R. flavipes workers were allowed to navigate the arena for 96 h. The arena was disassembled and analyzed for [ 14C] fipronil residues using liquid scintillation counting. An average of 0.92±0.1 ng/cm2 fipronil was recovered from gallery segments ≤ 5.12 cm from the treated soil zone in all treatments. Lower amounts of fipronil (0.046 ±0.1 ng/cm2) were recovered in gallery segments 5.12-45.72 cm from the treated soil. Our findings indicate that translocation of [14C] fipronil by termites only occurred over very short distances.
The mineralization of pesticides is generally a result of microbial activity. The mineralization of termiticides in soils around urban structures has not been reported previously in the scientific literature. We investigated the mineralization of indoxacarb 14.5% AI 150SC termiticide in urban soils collected from potential treatment zones. Soil cores (0-25cm and 76-102cm depth) were taken either 0.16 m or 3 m from foundation of structures. These soils were prepared and placed in individual soil microcosms treated with indoxacarb spiked with radiolabeled indoxacarb [AI]. Microcosms were held at 15 or 25°C and intermittently sampled for up to 203 d. Evolved 14CO2 was collected in sodium hydroxide traps and analyzed using liquid scintillation counting. Temperature had the biggest influence on mineralization rates as cumulative percent 14CO2 was highest at 25°C. Soil depth was not significant factor when subjected to the same temperature. Temperature was also used as an indicator of microbial activity as soils were analyzed for temporal changes in indoxacarb concentrations when held at 4, 15, and 30°C. High temperatures inversely affected indoxacarb residues in soil. In addition to temperature, residue formation and/or abiotic factors also contributed to significant overall loss(19.3-92.9%) of indoxacarb residue at 360 d with variation due to temperature and soil type.
In this study, the genetic structure of Iranian honey bee (Apis mellifera meda) populations, mainly obtained from all of regions, were investigated at two different mitochondrial regions. A total of 300 worker bees were collected from 20 different populations in 20 different locations. Portions of the mitochondrial 16S ribosomal RNA (16S rDNA) and cytochrome C oxidase I (COI) genes were amplified by PCR and then subjected to RFLP pattern analysis using 8 restriction enzymes. Nucleotide polymorphisms were revealed using restriction enzyme Sau3A I, Ssp I and Taq I in COI and Bsp143I, Ssp I and Dra I in the 16S rDNA gene segment. In this study, 3 novel composite genotypes (haplotypes) were found in Iranian honey bee populations. The average haplotype diversity (h) within populations was 0.0405. Heterozygosity values, Shannon index and the number of alleles of Iranian honey bee populations were low that could be caused by low definite geographic structure of Iranian honey bee populations. Genetic distance (D) values were found to be low (0.0–0.0011) within Iranian honey bee populations. Cluster analysis based on UPGMA method revealed that all populations and samples groups be in one cluster. Also, the phylogenetic tree based on Neighbor-joining method divided 29 subspecies of honey bee to 5 distinct clusters. The Iranian subspecies honey bee composed of a shared clade with subspecies of Eastern Mediterranean, Near East and Eastern parts of Middle East (O branch). This result is very useful for the control of conservation of local honey bees, as the movement of colonies across the border line of these neighboring countries, may affect the genetic structure of honey bee populations.
Seventeen polymorphic microsatellite DNA loci for Copototermes formo-sanus'wcre. isolated and characterized. Polymorphism of these loci was assessed in a sample of 32 unrelated C.formosanus individuals. An average of 4.6 alleles per locus (3-8 alleles) was detected. Observed and expected heterozygosities ranged from 0.2500 to 1.0000 and from 0.5591 to 0.8562, respectively. Six loci were found to have deviated from Hardy-Weinberg equilibrium in the sampled population after Bonferroni correction. No significant linkage disequilibrium was detected. These markers will be useful in population genetics, phylogenies and other relevant studies of C. formosanus.
Social wasps use different substrates for nesting, such as plants, rocks, and human buildings, and may adopt different strategies to protect their colony and brood. Here, we report the nesting behavior of Polistes versicolor in the deciduous forest, Northern Minas Gerais state, Brazil. The occurrences were recorded during fieldwork from February to December 2021. We found 30 colonies in eight plant species. The statistics demonstrate a preference of this social wasp for the plant Cereus jamacaru Cactaceae, which is used for nestings over a large area. Also, we report the first known record of P. versicolor colonies on the Acacia plumosa, Commiphora leptophloeos, Quiabentia zehntneri, and Ziziphus joazeiro, all of them with thorns. From the preference of P. versicolor for plants with thorns, we conclude this study to reinforce the role of these vegetal structures in protecting the colonies.
Undifferentiated termite larvae (workers) of Coptotermes formosanus Shiraki were first exposed to 18-month-old fipronil-treated sandy loam [0.5, 1.0 and 5.0 ppm (m/m) fipronil in the sandy loam] for one hour to obtain fipronil-exposed workers. The exposed workers were then mixed with unexposed workers at mixing ratios of 1:1 and 1:10 (exposed vs. unexposed) to examine the transfer of fipronil from exposed to unexposed workers. At a mixing ratio of 1:1, mortality of exposed workers decreased by 17-57% after 18 months of storage in the dark. No termites were dead at 0.5 ppm, whereas 26.7% mortality was recorded with freshly treated sandy loam. Mortality of unexposed workers was lower after storage, especially at 5.0 ppm. Mortality rates of exposed workers at a mixing ratio of 1:10 were generally similar to those at 1:1, as expected. However, unexpectedly, more unexposed workers died after storage than those with freshly treated sandy soil. The present results seem to indicate that the active ingredient (fipronil) in treated sandy loam was degraded to some extent during 18 months of storage even in the dry and dark condition, and as a consequence the termiticidal effect became lower than that of freshly treated sandy loam.
The knowledge on plant species used for the collection of floral resources is crucial to understanding interactions between plants and bees. The aim of the present study was to identify floral resources used by Centris analis and Centris terminata to provision brood cells and determine the niche breadth and overlap of these two species in a fragment of the Atlantic Forest in Brazil. This study was conducted at the Universidade Federal da Bahia and Parque Zoobotânico Getúlio Vargas, both of which are located in urban areas of the city of Salvador in the state of Bahia. Twelve and eight pollen types were identified in C. analis and C. terminata nests, respectively. The most frequent pollen types were from species of Malpighiaceae and Fabaceae. A larger trophic niche breadth was found in the Parque Zoobotânico Getúlio Vargas for C. analis and in the Universidade Federal da Bahia for C. terminata. Pianka’s index demonstrated trophic niche overlap between C. analis and C. terminata, which was greater in the Parque Zoobotânico Getúlio Vargas. This study is the first to provide data on plants used as food sources by species of the genus Centris in a fragment of the Atlantic Forest situated within urban areas.
This study aimed to identify the pollen grains found in honeys of Melipona (Michmelia) seminigra pernigra Moure & Kerr and Melipona (Melikerria) interrupta Latreille in two communities of the Tapajós-Arapiuns Extractive Reserve, Lower Amazon (Pará, Brazil) between December 2016 and November 2017. Twenty-four samples of honey were processed, 12 samples from M. seminigra pernigra collected in the Suruacá community and 12 samples from M. interrupta in the Vila Franca community. After acetolysis, 103 pollen types were identified, distributed across 22 families, plus eight indeterminate types. Fifty-nine types were exclusive to M. seminigra pernigra, 29 types were exclusive to M. interrupta and 15 pollen types were shared between both species. Anacardiaceae, Burseraceae, Melastomataceae, and Myrtaceae were the most attractive pollen families, providing key resources for maintenance of these bee populations. The sharing of pollen types between both bee species revealed a high similarity in preference for certain resources. M. seminigra showed greater diversity (H’ = 1.928) than M. interrupta (H’ = 1.292). Furthermore, the diversity (H’) and equitability (J’) indexes showed a more homogeneous pattern in the pollen spectrum of honeys from M. seminigra in most months studied. These data suggest that meliponiculturists should consider the diversity of plant species found in the two communities and keep them close to the meliponary, which will favor honey management and production, as well as the local biodiversity.
The floristic composition of an environment is important to ensure the trophic niche of bee species. Melipona scutellaris Latreille, is a typical stingless bee of Atlantic rainforest sites in northeastern Brazil, a region widely established in meliponaries for honey and pollen production. M. scutellaris is reared (meliponiculture) in rural and urban areas, where the species depends on the availability of different plants for nectar and pollen collection. In this study, we estimated food niche width, equitativity, and similarity between different colonies of M. scutellaris in highly urbanized and industrialized sites of the Metropolitan Region of Salvador, Bahia State, Brazil. We analyzed pollen spectrum of 58 honey samples from six meliponaries, during 12 months. We identified 111 pollen types distributed in 28 plant families. The Fabaceae family showed the highest diversity in pollen types (33.33% of the total) and Mimosa caesalpiniifolia was the most frequent pollen type, found in 100% of the samples. M. scutellaris concentrated its foraging activity on a few trophic resources (H’ = 2.69 and J’ = 0.01) indicating a few melittophilous plant species belonging to the genera Eucalyptus, Mimosa, Protium, Serjania and Tapirira, should be managed on a regional scale to favor meliponiculture with this native bee species.
Entomopathogenic fungi are frequently used as an alternative method for insect pest control. However, only a few studies have focused on the effect of these fungi on bees and on the selectivity of fungi to beneficial organisms in agroecosystems. The objective of the present study was to assess the susceptibility of worker bees of the species Melipona scutellaris (locally known as "uruçu") to the isolate (Biofungi 1) of the entomopathogenic fungus Beauveria bassiana. The experiment was carried through indirect contact between the fungal suspension and newly-emerged bees and topical application of the fungal suspension on the back of newly-emerged bees. The sampling design was completely randomized and comprised five treatments, which included four different concentrations of the fungus: 1 × 10 5, 1 × 106, 1 × 107, 1 × 108 conidia/ml, and a control composed of distilled water. Each treatment had five replicates. The mortality data were subjected to an analysis of variance and a probit regression analysis, which provided an estimate of the lethal dose to 50% of the population (LD50). The adjustment of the curves to the model was tested with a chi-squared test and differences between curves were tested with a test for parallelism. Beauveria bassiana was virulent to uruçu bees, killing the bees at the lowest dose used. These findings may help minimize the impact of this entomopathogen and, therefore, contribute to the maintenance of natural populations of these insects.
The bee species Melipona scutellaris Latreille, 1811 (Hymenoptera: Apidae) is native to Brazil and, stingless. In Brazil, stingless bees are responsible for 40% to 90% of tree species pollination, depending on the considered ecosystem. However, their survival has been threatened since the country has been standing out as a big consumer of pesticides. Many of the pesticides used are considered toxic to bees, including imidacloprid. Although the bees are not the target of these substances, they are highly vulnerable to contamination. Thereby, the objective of this study was to establish the mean lethal dose (LD50) and the mean lethal concentration (LC50) of imidacloprid for the M. scutellaris. In order to carry out this experiment, bees were collected and the test was performed according to OECD's protocol (1998a, 1998b), developed for A. mellifera. For the determination of LD50 and LC50, data was analyzed through the Probit method. The topical LD50 established in this study was 2.41 ng/ bee for 24 hours and 1.29 ng/bee for 48 hours. The oral LC50 was 2.01 ng i.a./mu L for 24 hours and 0.81 ng i.a./mu L for 48 hours. Thus, it is important to establish management methods which take this higher susceptibility into account to protect native species.
Stingless bees are important floral visitors in tropical ecosystems and through pollination, play a key role in maintaining biodiversity and perpetuating native plant species. In this context, knowledge about the flora used by stingless bees is essential to promote their conservation in natural environments. This study had the objective of analyzing the pollen stored by Tetragonisca angustula (Latreille, 1811) in an Atlantic Forest area. A total of 27 pollen samples were collected from six colonies from April 2013 to March 2014. The samples were processed using acetolysis, in which pollen types were identified, photomicrographs and their frequency values were estimated. The most representative pollen types had their pollen morphology described. The analysis of the pollen sediment revealed 53 pollen types, three of which were indeterminate and the others belonged to 26 families. Among the registered pollen types, only 13 (distributed in ten families) showed frequency values over 10% in the analyzed samples, in which the majority presented a pollen morphology classified as microreticulated and tricolporate small monads. The pollen types Byrsonima (with frequency between 0.05 to 82.79%, which was recorded throughout the entire study period), Tapirira guianensis (0.92 to 55.65%), and Cecropia (0.24 to 49.32%), stood out as an important source of trophic resources for the maintenance and survival of T. angustula in an Atlantic Forest area. In addition, this study highlights the importance of palynological analysis for the knowledge of trophic resources used by stingless bees.
In this study, the morphometric diversity and phylogenetic relationships of Iranian honey bee populations, were investigated using 14 morphometric characteristics. A total of 2250 young adult worker bees from 20 different populations in 20 different provinces of Iran were collected during June to October 2014. The results of nested analysis of variance showed that there were significant differences (P<0.01) between the provinces for all analyzed morphometric traits indicating the existence of a diversity among them. Correlation coefficient analysis showed a high degree of association among the most of the traits. This correlation coefficient should be a putative mean to improve of certain characters in breeding of honey bee. Principal component analysis revealed three principal components explained 81.5% of the total variation. Cluster analysis using WARD method classified honey bee populations into two main groups. The first group includes the honey bees collected from North, Northwest and West portions of Iran. The second group was represented by the honey bees from Eastern North, Central and Southern regions of Iran. The phylogenetic tree based on UPGMA method divided 29 subspecies of honey bee to 5 distinct clusters. The Iranian subspecies honey bee composed of a shared clade with subspecies of Eastern Mediterranean, Near East and Eastern parts of Middle East (O branch).
Dolichoderus Lund, 1831 is one of the large ant genera in the world and belongs to the subfamily Dolichoderinae. Currently, 130 species and 19 subspecies are known in this genus. A new species of the Dolichoderus thoracicus species group, Dolichoderus bakhtiari sp. nov., is here described based on the worker caste. The type series of the new species were collected from the shrub tree in hill evergreen forest (ca. 800 m a.s.l.). A list of the species and subspecies of the Dolichoderus thoracicus species group is provided.
Bee males are sometimes found forming sleeping aggregations on stems of bushes or trees to sleep at night, but there is no complete understanding of the reasons for this behaviour. This note describes the behavior of Melissodes (Ecplectica) nigroaenea (Smith, 1854) males forming temporary sleeping aggregations in dry inflorescences of Bidens pilosa L. The sleeping aggregations of M. nigroaenea were observed for approximately 15 days in an area of Cerrado, Brasília, DF. During the day M. nigroaenea males visit flowers of Cosmos sulphureus Cav. near the sleeping aggregations, where the females collect pollen. In the late afternoon, the males return to the sleeping aggregations, where they sleep at night. These data provide new information about the behavior of M. nigroaenea males.
Podium denticulatum occurs from Mexico to southern Brazil, including northeastern Argentina. Females use pre-existing cavities to build nests, consisting of cells separated by walls of mud and resin and massively provisioned with paralyzed cockroaches. Trap nests were disposed in three localities in the state of São Paulo, Brazil (Araras, São Carlos, Rifaina), resulting in the collection of 201 nests from December/2003 to June/2007. The founding nests were brought to the laboratory, opened and the pupae transferred to identified vials until the emergence of the adults, when they were then weighed, sexed and stored at -20ºC. The nesting activity was seasonal, with a higher number of nests in the warm and rainy season of the year. The number of constructed cells ranged from one to nine per nest. The emergence rate of adults in the 716 brood cells was 74%, with homogeneous distribution of mortality by egg, larva and pupa stages. This mortality was partly due to parasitism observed in 39% of nests, predominantly by Melittobia sp. and rarely by Diptera (Tachinidae). A 1:1 sex ratio was observed among the newly emerged adults of each locality analyzed. Strong sexual dimorphism was characterized by linear measurements of wings and body mass, with females and males showing a mass between 27-116 mg and 14-70 mg, respectively. The geometric morphometry confirmed this dimorphism and revealed significant variation of wing size and shape among individuals of the analyzed populations, a result that deserves subsequent studies to point out the factors that account for this differentiation.
In this study, we investigated the effect of starvation on the feeding behavior of the ant Tapinoma nigerrimum. In particular, we tested the response of ants that had experienced different levels of starvation, toward sucrose solutions of increasing concentration. As expected, starved ants promptly reacted to the sugary food sources with a higher rate of acceptance as compared to satiated ones. Acceptance increased both with sugar concentration and the length of the starvation period. However, a consistent fraction of the starved ants did not feed on the solutions, suggesting that starvation had different effects on different individuals, even though they all had food ad libitum before the beginning of the tests, had comparable body sizes, and were collected from the same trail. The different acceptance of sugary solutions may be, therefore, merely because ants fed on the experimental food at different times. Interestingly, in all the experimental groups, ants appeared to satiate quickly, irrespective of the solution tested and fasting duration. This would suggest that the rate of ingestion was independent of these factors, a result partially at odds with previous studies. This study is one of the few ones dealing with the behavioral response of an ant species to a famine event.
The aim of the present paper is to study magnetosensibility and to seek for magnetic nanoparticles in ants. The social insects, by living in colonies, developed very efficient methods of nestmate recognition, being less tolerant towards individuals from other colonies. Therefore, any kind of strange behavior between nestmates and/or conspecifics, besides those present in their own behavioral repertoire, is not expected. The behavior study in the present paper analyze whether changes in the intensity of applied magnetic fields on Ectatomma brunneun (Smith) ants can cause changes in the normal pattern of interaction between conspecifics. A pair of coils generating a magnetic field was used to change the whole local geomagnetic field. Magnetometry studies were done on abdomens and head + antennae using a SQUID magnetometer. The results show that changes in the geomagnetic field affect the usual pattern of interactions between workers from different colonies. The magnetometry results show that abdomens present superparamagnetic nanoparticles and heads present magnetic single domain nanoparticles. Behavior experiments show for the first time that Ectatomma brunneun ants are magnetosensible. The change in nestmate recognition of Ectatomma ants observed while a magnetic field is applied can be associated to some kind of disturbance in a magnetosensor presented in the body based on magnetic nanoparticles.
Ants can act as seed dispersers, modifying their distribution, affecting the reproductive success and the vegetation spatial structure. The leaf-cutting ants function, as dispersers of non-myrmecochorous plants, is little known. This work aimed to evaluate descriptively the Atta laevigata interaction with Solanum lycocarpum diaspores. The observations were carried out, throughout 10 days, in a secondary fragment of Semidecidual Seasonal Forest in Ivinhema, MS. To determine the removal rate, 500 seeds were taken from ripe fruits, dried, labeled and distributed in groups ranged from five to 50 seeds, totaling 100 seeds per foraging trail. Groups of 30 seeds with pulp were also distributed every 1.0 m on the trails. Individuals of different sizes presented different interactions to the fruits and seeds, smaller workers carried pulp or seeds separately, medium workers carried seeds with pulp or cleaned them before carry to the nest and the largest workers carried the seeds to the nest. Atta laevigata acted primarily as predators, with few seeds discarded. Their actions may interfere in the native vegetation regeneration, with a significant role in removing S. lycocarpum seeds, a pioneer species, and in population control for this species by the severe predation of seeds. However, the remaining1.6% intact seeds allows germination, with the A. laevigata acting as a seed dispersers over short distances for this species, favoring the S. lycocarpum dispersion.
The taxonomic status of Platythyrea is still confused because there is high phenotypic plasticity, possible taxonomic synonyms and morphological proximity with other species of the same genus. The correct identification of Platythyrea sinuata depends on interdisciplinary analyzes with a morphological and genetic approach. Here we provide the description of karyotype for P. sinuata, 2k=24M+20A with CMA3+/DAPI- on single chromosome. This data will be helpful to the understanding of the taxonomic status of this species.
The chromosome variability among ant species is remarkable, and the processes generating such variation are still under discussion since polyploidy has been observed in some distinct taxa. The chromosome number of species belonging to the Camponotus, subgenera Myrmothrix and Myrmobrachys, are highly different, whereas, the first subgenus has double the number of chromosomes of the second. In order to test the hypothesis of chromosome number doubling through polyploidy, the genome sizes of Camponotus (Myrmothrix) rufipes, Camponotus (Myrmothrix) renggeri and Camponotus (Myrmobrachys) crassus were estimated by flow cytometry. The chromosome number of specimens from the nests studied was also defined. No significant variation was noted in the genome size among them. The mean haploid genome size value (1C) of workers for the three species was 286.16 Mpb (0.29 pg). The polyploidy hypothesis can be ruled out as an evolutionary step linking the karyotype variations among the three studied species since the genome size of C. crassus with 2n = 20 chromosomes was the same as that of C. rufipes and C. renggeri with 2n = 40. The lack of variation in the amount of DNA between the related species C. rufipes and C. renggeri also demonstrate that flow cytometry is not an adequate approach to distinguish them. Our results highlight the importance of combining distinct methods, DNA quantification, and cytogenetics from the same colony. Understanding the path of chromosome evolution of three species with distinct degrees of relatedness should provide further information in enriching our knowledge about the Minimum Interaction Theory.