Fig 2
Number of subadult and adult females (filled circles) of Allocyclosa bifurca and the percentage of parasitism (open circles), from December 2003 to May 2006 on the campus of the Universidad de Costa Rica, San Jose Province.
Source publication
The rates of parasitism of Theridion evexum by the parasitoid wasp Zatypota petronae, and Allocyclosa bifurca by Polysphincta gutfreundi, were followed for two years. Parasitism of T. evexum was very low (mean 1.39 +/- 1.8%), and restricted to nearly seven months of the year. Parasitism of A. bifurca was higher (mean 7.8 +/- 7.6%), and did not show...
Context in source publication
Context 1
... mean rate of parasitism of T. evexum was 1.39 ± 1.80%, and did not exceeded 7.7% in any census. Parasites were only found on larger immature spiders, and thus occurred during the second half of each annual peak of abundance (Fig. 1). Parasites were only found on larger immature spiders (apparently fourth instar up to subadults), and thus occurred during the second half of each annual peak of abundance (Fig. 1); they were not present on adults or younger spiderlings. Parasitism in A. bifurca was much higher, with an overall mean of 7.8 ± 7.6% and a maximum of 29.6%. Parasitized spiders were found in most censuses (Fig. 2), and parasites were found only on subadult and adult ...
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Citations
... The short lifespans of adult male spiders exclude them as suitable hosts for the development of parasitoid larvae (Fitton et al. 1987). Although in the Temperate zone with changing seasons, the preference for juvenile spiders is the rule for polysphinctines (e.g., Korenko et al. 2011), in the Neotropics several polysphinctines prefer subadult and adult female spiders (Barrantes et al. 2008;Eberhard and Gonzaga 2019). This is certainly linked to the significantly larger wasp sizes in the Neotropics and consequently a preference for larger-i.e., subadult or adult-spiders. ...
... The parasitism rate can differ considerably among spider taxa. For example, Barrantes et al. (2008) found substantial differences in the parasitism rate between the spiders Theridion evexum Keyserling, 1884, with a parasitism rate of 1.39% ± 1.80% and Allocyclosa bifurca (McCook, 1887), with a parasitism rate of 7.8% ± 7.6%. This agrees with our results, and this variability in the parasitism rate among species may explain the variability in the parasitism rate among localities. ...
The evolutionary processes that shape host‐parasitoid coexistence in a changing environment are poorly understood. We examined the large‐scale distribution of highly specialised polysphinctine Darwin wasps associated with spiders along an elevational gradient and tested the hypothesis that distribution and parasitism rates depend on elevation, habitat type and the species and age composition of the host community. Further, on the basis of a large‐scale dataset, we examined the hypothesis that three‐dimensional webs in spiders may be an evolutionary adaptation against polysphinctine parasitoids. We found significant variation in parasitoid distribution and parasitism rates along a 1500 m elevational gradient in central Europe. The optimal model showed a humped shape for the parasitism rate on an elevational gradient. Overall, we found relatively low parasitism rates (4%) on spiders, with the highest parasitism rates in non‐forested riparian vegetation and the lowest in agroecosystems. Rates of parasitism varied significantly among spiders forming different types of webs (foraging guilds). Spiders spinning 3D webs were dominant in the spider community, but parasitism on them was lower compared to spiders spinning 2D webs, probably because of the defensive function of the 3D web architecture. The bottom‐up approach, in which the entire spider host community is analysed for parasitism rate, supports the hypothesis that 3D webs are evolutionarily novel and could have arisen as a result of the need for defence against enemies such as parasitoids.
... This suggests that different factors drive the number of egg sacs parasitized versus the proportion of eggs parasitized within egg sacs. The prevalence of egg sacs parasitized is directly related to the probability of parasitoids finding egg sacs, which could be affected by at least three factors: abundance and density of egg sacs, age of the eggs (eggs can be parasitized for only a short period after being laid [69]), and abundance of parasitoids [70]. However, once a parasitoid finds an egg sac, the number of spider eggs attacked depends on other factors, like the number of eggs present in the parasitoid's ovarioles, the number of female parasitoids that oviposit into a single egg sac, and the proportion of eggs within the sac that are accessible to the parasitoids. ...
Parasitoidism strongly influences the structure of the spiders’ populations, and it can be affected by environmental factors such as those caused by anthropogenic actions. We studied the prevalence of parasitoids in egg sacs and the proportion of eggs parasitized in each egg sac of two synanthropic spider species, one native to the American continent (Parasteatoda tepidariorum) and another recently introduced to the Americas (Latrodectus geometricus). We conducted the study at two scales, along an urban gradient (from highly urbanized to rural sites) and in the vegetation surrounding each sampling site (microscale). We expected to find a larger prevalence of parasitoids in the most urbanized sites and around sampling sites with more vegetation. However, we saw more parasitized egg sacs at the intermediate urbanized site for both species, and the vegetation surrounding the sampling sites did not affect the number of parasitized egg sacs. Therefore, conditions in the site with intermediate urban development favored parasitoids. We also found more parasitized egg sacs in P. tepidariorum than in L. geometricus, which is likely a consequence of native parasites not being adapted to a new host. The proportion of eggs parasitized was similar for both species in all sites, which may be related to the behavior (e.g., searching behavior) and number of spider eggs a female parasitoid can parasitize.
... Inside this refuge, the spider deposits up to four egg sacs and provides maternal care. Currently there are some records of species of Theridion being parasitized by Zatypota wasps in the temperate (Fitton et al. 1987;Gauld & Dubois 2006) and Neotropical region (Weng & Barrantes 2007;Barrantes et al. 2008). In this study, we present new information about the biology of a new interaction between the parasitoid spider wasp Zatypota riverai and the host spider Theridion sp. ...
The hymenopteran genus Zatypota Forster, 1869 (Ichneumonidae: Pimplinae, Ephialtini) comprises highly specialized koinobiont ectoparasitoids of spiders and is the largest genus of the Polysphincta group of genera in the world, with more than 50 described species. The vast majority of species of Zatypota are parasitoids of the spider family Theridiidae. In this study, we present information about a new interaction between the parasitoid spider wasp Zatypota riverai Gauld, 1991 and the host spider Theridion sp. Walckenaer, 1805 (Theridiidae) with information about host weight selection. We collected 102 non-parasitized adult and subadult females of Theridion sp. and six spiders with larvae of Z. riverai attached to host’s abdomen. The pupal development takes about 8–11 days, though the development time of the pupa varies with the sex of the wasp. All larvae collected in the field completed their life cycle on the host spiders, even though all of the hosts were small, indicating that the host biomass was sufficient for larval development and no largersized spiders are needed. Moreover, larger Theridion probably pose a greater risk because they are more likely to be successful at wasp predation, even if they offer a greater resource to the larva.
... Repeated checks of spiders from 22 Jan to 3 March 2004 at two sites on the UCR campus showed that one site, which was checked six times, had 20 parasitoids in 133 checks of spiders (many individual spiders were checked repeatedly, but parasitized individuals were counted only once); checks on the same dates at another site less than 100 m away revealed only 8 parasitoids in 228 checks (Chi2 = 15.6, df = 1, p < 0.001). The significant autocorrelations between parasitism rates at particular sites on the UCR campus in successive surveys that were made at approximately two week intervals (Barrantes et al., 2008) also suggest clumped searching behavior by the wasps. Fig. 2. a) An A. bifurca spider rests at the hub of an orb that has a small tangle near its lower surface. ...
... H. argyraphaga (2) the numbers of parasitized spiders in clumps increased gradually rather than abruptly. The spatial clumping of parasitism documented here may explain the temporal clumping of parasitism rates that was noted previously in this species on the basis of autocorrelations of parasitism rates in successive census counts (Barrantes et al., 2008). ...
Wasps of the Polysphincta clade are known to manipulate the behavior of their web-building spider hosts by injecting psychotropic chemicals, but the methods they use to hunt spiders are poorly documented. In 25 attacks observed over several years in the field in the Valle Central of Costa Rica, Polysphincta gutfreundi showed great flexibility. Wasps employed three basic hunting tactics to subdue the host spider Allocyclosa bifurca: strike the spider at its resting site at the hub of its orb web; land in the sticky spiral of the web, struggle, and then attack the spider when it approached; and wait immobile at the hub to await the return of a spider that had fled. The wasps moved and oriented agilely on their hosts' orbs. The only repeatedly effective spider defense was to drop immediately from the web and remain away for many minutes. Parasitism was strongly clumped spatially, suggesting that female wasps may learn where to hunt. Nearly all the details of P. gutfreundi attack behavior have also been observed in other species of the Polysphincta clade. They include the use of multiple attack strategies, surprise attacks from the air on spiders resting on their webs, attacks through the hub, agile movements on the spider's web, inducing the spider to approach by apparent imitation of prey, waiting for long periods in the web poised to strike, and inserting the ovipositor into the anterior end of the spider's cephalothorax. One unique detail of attack behavior in P. gutfreundi was to shuttle rapidly to the other side of the hub to reach the spider. Few of the spider's defensive traits were effective against these wasps. Species in the Polysphincta group are behaviorally flexible, but as a group these wasps utilize relatively uniform tactics to subdue their hosts.
... References: (1) Barrantes et al. (2008); (2) (2007). Information on the presence of sticky lines in normal webs of theriidids was obtained from Eberhard et al. (2008) or from the references included in the have been described. ...
Wasps in the Polysphincta group of Ichneumonidae induce their web-spinning spider hosts to construct modified ‘cocoon’ webs that support and protect the wasps’ cocoons, but the mechanisms used by wasps to manipulate their host spiders have been unclear. We evaluate the hypothesis that wasps manipulate spider ecdysteroid moulting hormones, using the taxonomic distribution of the hosts and cocoon web types of different wasp lineages in the Polysphincta group, with new data comparing cocoon webs with the moulting webs of non-parasitized host spiders. Several predictions were confirmed: wasp and spider species have not co-evolved in a strict sense, with wasp lineages jumping between host lineages; cocoon web designs induced by closely related wasps varied widely in spiders with differing natural histories; cocoon web designs were consistently adjusted to the natural history of the spider in ways promoting wasp survival; and cocoon web designs often resembled those of moulting webs of non-parasitized spiders. Several other types of data did not fit the predictions of simple versions of the ecdysteroid hypothesis, however. We conclude that the use of ecdysteroids by the wasps to manipulate host spider behaviour is probably widespread, but that some wasps might also use other mechanisms.
... Inside this refuge, the spider deposits up to four egg sacs and provides maternal care. Currently there are some records of species of Theridion being parasitized by Zatypota wasps in the temperate (Fitton et al. 1987;Gauld & Dubois 2006) and Neotropical region (Weng & Barrantes 2007;Barrantes et al. 2008). In this study, we present new information about the biology of a new interaction between the parasitoid spider wasp Zatypota riverai and the host spider Theridion sp. ...
The hymenopteran genus Zatypota Fo¨rster, 1869 (Ichneumonidae: Pimplinae, Ephialtini) comprises highly specialized koinobiont ectoparasitoids of spiders and is the largest genus of the Polysphincta group of genera in the world, with more than 50 described species. The vast majority of species of Zatypota are parasitoids of the spider family
Theridiidae. In this study, we present information about a new interaction between the parasitoid spider wasp Zatypota riverai Gauld, 1991 and the host spider Theridion sp. Walckenaer, 1805 (Theridiidae) with information about host weight selection. We collected 102 non-parasitized adult and subadult females of Theridion sp. and six spiders with larvae of Z. riverai attached to host’s abdomen. The pupal development takes about 8–11 days, though the development time of the pupa varies with the sex of the wasp. All larvae collected in the field completed their life cycle on the host spiders, even though all of the hosts were small, indicating that the host biomass was sufficient for larval development and no largersized spiders are needed. Moreover, larger Theridion probably pose a greater risk because they are more likely to be successful at wasp predation, even if they offer a greater resource to the larva.
... We found that P. sinearanea sp. n. has a relatively high incidence of parasitism in the M. laticeps population, compared with other species of the tribe Polysphinctini (Gonzaga & Sobczak 2007;Barrantes et al. 2008;Eberhard 2013;Korenko et al. 2014; but see Eberhard 2000b). The 25.5% parasitism of M. laticeps is similar to the 29.6% maximum reported for Polysphincta gutfreundi Gauld, 1991parasitizing Allocyclosa bifurca (McCook, 1887 (Barrantes et al. 2008) and Polysphincta janzeni Gauld, 1991 parasitizing Cyclosa morretes Levi, 1999 (23.39%;Kloss et al. 2016b). ...
... n. has a relatively high incidence of parasitism in the M. laticeps population, compared with other species of the tribe Polysphinctini (Gonzaga & Sobczak 2007;Barrantes et al. 2008;Eberhard 2013;Korenko et al. 2014; but see Eberhard 2000b). The 25.5% parasitism of M. laticeps is similar to the 29.6% maximum reported for Polysphincta gutfreundi Gauld, 1991parasitizing Allocyclosa bifurca (McCook, 1887 (Barrantes et al. 2008) and Polysphincta janzeni Gauld, 1991 parasitizing Cyclosa morretes Levi, 1999 (23.39%;Kloss et al. 2016b). It is known that the incidence of parasitism varies among the polysphinctine species, host populations, and seasons (Weng & Barrantes 2007;Barrantes et al. 2008;Korenko et al. 2011;Takasuka & Tanaka 2013;Kloss et al. 2016b) and probably is higher during periods with higher numbers of available hosts (Gonzaga et al. 2015b). ...
... The 25.5% parasitism of M. laticeps is similar to the 29.6% maximum reported for Polysphincta gutfreundi Gauld, 1991parasitizing Allocyclosa bifurca (McCook, 1887 (Barrantes et al. 2008) and Polysphincta janzeni Gauld, 1991 parasitizing Cyclosa morretes Levi, 1999 (23.39%;Kloss et al. 2016b). It is known that the incidence of parasitism varies among the polysphinctine species, host populations, and seasons (Weng & Barrantes 2007;Barrantes et al. 2008;Korenko et al. 2011;Takasuka & Tanaka 2013;Kloss et al. 2016b) and probably is higher during periods with higher numbers of available hosts (Gonzaga et al. 2015b). In the wet season, when we evaluated the incidence of parasitism, only adults and subadults were present in the studied population of M. laticeps (T. ...
Parasitoids may change host behavior in order to improve their
survival during the pupal stage. This has been observed in some
ichneumonid wasps (Polysphincta genus group), which are able to induce
modifications in the movements of host spiders during web construction.
These changes usually result in web patterns distinct from those of
normal webs of spiders. In this study, we describe the behavioral change
in the orb-weaver spider Metazygia laticeps (Araneidae), parasitized by a
new species of parasitoid wasp, Polysphincta sinearanea sp. n.
(Ichneumonidae), which has a high prevalence in M. laticeps populations.
This parasitoid induces behavioral changes in M. laticeps that result in
the complete suppression of the normal orb-web structure. The absence of
the orb probably reduces accumulation of debris and interception of
insects by the webs (factors that could result in the rupture of threads
that hold the shelter of the web) during the period from cocoon
construction to the emergence of the adult wasp. Also, the suppression of
the normal orb-web structure implies that resources that would have been
invested in the web will be available to the larva wasp.
... In highly specialist parasitoids, their development and lifecycle are closely synchronized with those of their host species (Barrantes et al. 2008). Koinobionts are usually considered as more host-specific (Althoff 2003). ...
Parasitoids are characterized by a defined range of hosts, either more specialist or generalist. Under natural conditions, females may encounter different host species on the same plant or in the same location. In this case, their preference for one host could influence their choice. However, the presence of less suitable hosts may also affect their choice and, in some cases, may reduce their interest in a patch where both preferred and less preferred hosts are available. The aim of the present study was to test the consequences of the simultaneous presence of three cereal aphids (Sitobion avenae Fabricius, Metopolophium dirhodum Walker, and Rhopalosiphum padi Linnaeus) on the parasitism by two of their parasitoids, Aphidius ervi Haliday and Praon volucre Haliday. Firstly, in the no-choice experiment, A. ervi parasitized on S. avenae at a significantly higher rate as compared to M. dirhodum, whereas no parasitism on R. padi was observed. P. volucre parasitized the three species of cereal aphids with a significant preference for S. avenae. Interestingly, when two or three host species were offered simultaneously in the same quantity to pairs of parasitoids, the level of parasitism was less than that observed for one host species alone. This observation exhibits a distractive effect on non-host species, from the defense mechanism of a non-suitable host or from the perception of bad quality patches. These results raise the question of the practical application of inundative release of parasitoids for biocontrol when several hosts are available simultaneously.
... In highly specialist parasitoids, their development and lifecycle are closely synchronized with those of their host species (Barrantes et al. 2008). Koinobionts are usually considered as more host-specific (Althoff 2003). ...
Parasitoids are characterized by a defined range of hosts, either more specialist or generalist. Under natural conditions, females may encounter different host species on the same plant or in the same location. In this case, their preference for one host could influence their choice. However, the presence of less suitable hosts may also affect their choice and, in some cases, may reduce their interest in a patch where both preferred and less preferred hosts are available. The aim of the present study was to test the consequences of the simultaneous presence of three cereal aphids (Sitobion avenae Fabricius, Metopolophium dirhodum Walker, and Rhopalosiphum padi Linnaeus) on the parasitism by two of their parasitoids, Aphidius ervi Haliday and Praon volucre Haliday. Firstly, in the no-choice experiment, A. ervi parasitized on S. avenae at a significantly higher rate as compared to M. dirhodum, whereas no parasitism on R. padi was observed. P. volucre parasitized the three species of cereal aphids with a significant preference for S. avenae. Interestingly, when two or three host species were offered simultaneously in the same quantity to pairs of parasitoids, the level of parasitism was less than that observed for one host species alone. This observation exhibits a distractive effect on non-host species, from the defense mechanism of a non-suitable host or from the perception of bad quality patches. These results raise the question of the practical application of inundative release of parasitoids for biocontrol when several hosts are available simultaneously.
... Host behaviour manipulation by parasites is a widespread phenomenon that has long aroused the curiosity of the scientific community (Cram 1931;van Dobben 1952;Holmes and Bethel 1972;Moore 1984; Barnard and Behnke 1990;Godfray 1994;Poulin 2000;Moore 2002; Thomas et al. 2005;Lafferty and Shaw 2013;Hafer 2016;Soghigian et al. 2017). For example, numerous publications report parasites of fish that alter the activity patterns and foraging locations of their intermediate hosts, making them especially susceptible to avian predators (Barber et al. 2000;Shaw et al. 2009). ...
Modified webs constructed by spiders parasitized by Ichneumonid wasps were first mentioned in literature in 1771. These initial observations were restricted to the description of the cocoon web spun by an unidentified spider species presenting a cocoon attached. Only in the year 2000 was the subject intensively studied in another host/parasitoid system. The interaction between Leucauge argyra (Tetragnathidae) and Hymenoepimecis argyraphaga (Ichneumonidae) was carefully described by W. G. Eberhard in Costa Rica. Web modifications, in this case, are even more extensive than those previously recorded. Cocoon webs spun by L. argyra are composed of just a few strong lines. Spirals are absent, and the cocoon remains suspended attached to the hub of the structure. From these studies up to now, several other cases have been described in the Neotropics. The initial doubt about the generality of host manipulation involving the Polysphincta genus-group was solved, but many questions arise from the subsequent studies. We still know almost nothing about the mechanisms involved in manipulation, for example. Recent studies suggest that it involves the injection of some substance by the parasitoid onto its host because the removal of the attached larva leads to a restoration of the original web patterns. Another interesting aspect is the investigation of how the structure of normal webs affects the design of cocoon webs. Finally, it is important to demonstrate that specific alterations in normal webs result in benefits to the manipulative wasp. The objectives of this chapter are to present an overview of recent discoveries involving these interactions, a brief historical summary of the researching efforts in the Neotropical region, and perspectives for future studies.
