Specialisation in prey capture drives coexistence among sympatric spider‐hunting wasps

1. Sister taxa that coexist in the same space and time often face competition due to the use of similar resources. However, some closely related species can adopt fine‐grained specialisation in resource use to coexist. This study investigated niche overlap between three sympatric spider‐hunting wasp species of the genus Trypoxylon (Hymenoptera: Crabronidae) known to nest in three of the habitats found in the study area. 2. First, the co‐occurrence of these wasp species in the three habitats was estimated, as a proxy for potential competition. Then, the following hypotheses were tested: (i) niche partitioning is seen more often between species that co‐occur in a habitat, whereas there is niche overlap between species nesting in distinct habitats (prey specialisation hypothesis); and (ii) wasp species capture prey according to their size (physical constraint hypothesis). 3. Two pairs of wasp species were found consistently nesting in the same habitat. Niche partitioning based on prey taxa occurred regardless of the habitat preference. It was also found that differences in the size of wasps reflected distinctions in the size of their prey. 4. These findings were consistent over the years, showing that the significance of specialisation in foraging activities and physical constraints during prey capture can play key roles in the coexistence of sympatric species. The distinctions in the foraging strategies of these wasps are discussed, as well as potential mechanisms driving the evolution in prey specialisation, with insights for future studies.     

Predicting ecological and phenotypic differentiation in the wild: a case of piscivorous fish in a fishless environment

Environmental variation drives ecological and phenotypic change. How predictable is differentiation in response to environmental change? Answering this question requires the development and testing of multifarious a priori predictions in natural systems. We employ this approach using Gobiomorus dormitor populations that have colonized inland blue holes differing in the availability of fish prey. We evaluated predictions of differences in demographics, habitat use, diet, locomotor and trophic morphology, and feeding kinematics and performance between G. dormitor populations inhabiting blue holes with and without fish prey. Populations of G. dormitor independently diverged between prey regimes, with broad agreement between observed differences and a priori predictions. For example, in populations lacking fish prey, we observed male‐biased sex ratios, a greater use of shallow‐water habitat, and larger population diet breadths as a result of greater individual diet specialization. Furthermore, we found predictable differences in body shape, mouth morphology, suction generation capacity, strike kinematics, and feeding performance on different prey types, consistent with the adaptation of G. dormitor to piscivory when coexisting with fish prey and to feeding on small invertebrates in their absence. The results of the present study suggest great potential in our ability to predict population responses to changing environments, which is an increasingly important capability in a human‐dominated, ever‐changing world. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 588–607.     

Size and sex of cricket prey predict capture by a sphecid wasp

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Differential diet breadths and species coexistence in leafroller-hunting eumenid wasps

There are, at least, three possible ways in which similar species coexist; resource partitioning, interference competition, and exploitation competition. Here, I investigated which way contributed to the coexistence of leafroller-hunting eumenid wasp species. Resource partitioning and, in addition, differential diet breadths proved to promote species coexistence in this case. First, I analyze the prey records and diet overlap of four eumenid species in a local area. The larger two eumenids hunted similar-sized prey items and had similar potential taxonomic prey uses. But the diet breadth of the subsocial eumenid was much wider than that of the solitary one. As a result, the diet overlap between the two large eumenids decreased. This was because the solitary eumenid attend repeatedly to the same hunting site inhabited by one abundant prey species, while the subsocial one made random hunting. On the other hand, the two medium-sized eumenids partitioned resources according to prey size. Secondly, I related these results to prey choice by several other species of eumenid obtained from literature sources. Ten Japanese common eumenids were divided into four groups according to their prey size. In each of the four groups, 2 to 3 wasp species differentiated the habitat (1 group) or coexisted by means of differential diet breadths (parallel with differential sociality, 2 groups).     

Predatory specialization in the wasp <Emphasis Type="Italic">Sphex ingens</Emphasis> for the capture of katydids

Sphex ingens is one of 30 species in the family Sphecidae that occur in the state of Rio de Janeiro. However, details of the behavior and sexual selection of natural populations of this wasp species have only recently been unveiled. In addition, the knowledge of its ecology is still poor. This is the first study on the feeding behavior interactions between S. ingens and prey captured to feed its larvae. Paralyzed prey were collected manually at the sites of wasp nests on Aventureiro Beach, Ilha Grande, Brazil during the provisioning activity of marked female S. ingens. All prey were preserved, their sex and sexual maturity were determined, and they were identified to the lowest possible taxonomic level. The body mass and size of the prey and female wasps were measured. Sphex ingens females captured only Pleminia vicina and Meroncidius sp. The body masses of wasps and katydids were positively correlated. The body mass of captured katydids was significantly dependent on the wasp’s wing length. Most of the prey were adult females, but the differences did not confirm possible preferences, as those values can be related to differences in the distribution and fluctuation in the population density of prey species and to the individual foraging strategies of female wasps. However, the predisposition to predatory specialization exhibited by S. ingens populations in Ilha Grande and elsewhere suggests that this interaction can be an important source of mortality for populations of pseudophylline katydid species.     

Complex interactions between components of individual prey specialization affect mechanisms of niche variation in a grasshopper-hunting wasp

1.?Individual foraging behaviour defines the use of resources by a given population and its variation in different ways such as, for example, unpredictable interactions between taxon-biased and size-biased selection. Here we investigated how the environmental availability of prey and individual specialization, for both prey taxa and prey size, shape niche variation across generations in the grasshopper-hunting digger wasp Stizus continuus. 2.?The population of S.?continuus expressed selective predation, females mainly hunting species encountered on large bushes; diet changed across generations, due more to size increase in potential prey than to changes in the orthopteran community. 3.?Individual females of both generations weakly overlapped the size and taxa of prey, and the niche width of the second generation increased for both prey size and taxa. 4.?The greater variance in prey size in the environment accounted for the enlarged prey size niche of the second generation, but the load-lifting constraints of the wasps maintained individual prey size specialization constant. In contrast, the enlarged prey taxon niche paralleled a smaller overlap of diets between wasps in the second generation. 5.?Increased niche width in the S.?continuus population was thus achieved in two ways. Regarding prey size, all individuals shifted towards the use of the full set of available resources (parallel release). For prey taxa, according to the classical niche variation hypothesis, individuals diverged to minimize resource use overlap and perhaps intraspecific competition. These two mechanisms were observed for the first time simultaneously in a single predator population.     

Wasp Attacks and Spider Defence in the Orb Weaving Species <Emphasis Type="Italic">Zygiella x-notata</Emphasis>

Predator–prey relationships are generally based on arm-race. Wasps and spiders are both predators, which could be potential prey for each other. The orb weaver spider Zygiella x-notata is sometimes a prey for the wasp Vespula germanica. We observed the wasp hunting behaviour under natural conditions, and we tested the influence of the spider’s behaviour on the wasp attack success. Wasps were active predators during the reproductive period of the spider. Results showed that wasps located more easily male spiders than females particularly when they were engaged in mate guarding. Female location depended on the presence of a web, but also of prey or prey remains in the web. On the other hand, their location depend neither on the characteristics and the position of the retreat in the environment nor on the size of the web. After location, males were more often captured than females whatever their behaviour (mate guarding or not). Presence of prey remains or prey in the web did not increase the risk for the spider to be captured. There was also no influence of the retreat’s characteristics or of its position in the habitat on the risk for the spider to be captured; but wasp successful attacks were less numerous when silk was present around the entrance of the retreat or when the spider was completely inside. As prey and prey remains favoured location of spiders by the wasps, we tested spider web cleaning behaviour as a response to wasp predatory pressure. By throwing small polystyrene pellets in the webs, we observed that more 80% of the spiders rejected the pellets in less than one minute. Our data indicated that wasps were significant predators of Z. x-notata and wasp attack could have been a selective pressure that had favoured spider defensive behaviours such as web cleaning.     

Morphological distance and inter-nest distance account for intra-specific prey overlap in digger wasps (Hymenoptera: Crabronidae)

Although inter-individual diet variation is common in predatory wasp populations, the factors accounting for such variation are still largely unknown. Here, we asked if paired diet dissimilarity in three species of digger wasps correlates with morphological distance and inter-nest distance, two factors previously linked to diet partitioning in vertebrates. Results sharply differed among species and generations. All sampled populations showed significant inter-individual diet variation for prey taxa, but only in half of the cases for prey size. In one generation of two species [Bembix zonata Klug and Stizus continuus (Klug)], similar-sized wasps had similar prey taxonomic spectra (and for S. continuus also similar prey size spectra), a phenomenon which probably reduces intra-specific competition. In addition, B. zonata females nesting closer to each other had more similar prey taxonomic spectra, suggesting that distant females probably hunt on different patches that harbour different prey species. For the females of a further species (Bembix merceti Parker), pairwise size difference and inter-nest distance did not affect prey dissimilarity. Both morphological distance and inter-nest distance are potentially important in shaping the overlap of individual resource use in wasps, though probably only in certain conditions such as a highly clumped distribution of nests and size-related constraints on prey selection.     

Host‐size decisions of female parasitoid wasps seeking hidden hosts

1. Choice of host size may play a critical role in parasitoid success, a task that takes on added complications when dealing with concealed hosts, but most such studies of insect behaviour have only taken place in the laboratory. 2. This study investigates the success of a wasp (Alabagrus texanus: Braconidae) in finding host caterpillars Herpetogramma theseusalis (Crambidae) of the most effectively handled size hidden in shelters, in both the field and the laboratory. 3. First, the study tested wasp preference and success in parasitizing large, middle‐sized and small caterpillars (> 5, 3–5, < 3 mm) presented in the open, one at a time, in the laboratory. The wasps attacked (inserted or attempted to insert their ovipositor) a higher proportion of middle‐sized (3–5 mm) caterpillars compared with either small (< 3 mm) or large (> 5 mm) caterpillars. Naïve wasps attacked large caterpillars more often than did experienced wasps. Wasps responded to increasing caterpillar size by increasing the number of legs used to pin their prey rather than by increasing handling time. 4. The frequencies of visits to shelters in the field containing a majority of either large or middle‐sized caterpillars were then compared, followed by a test providing the wasps with similar choices under controlled laboratory conditions. Wasps most frequently visited shelters containing a majority of middle‐sized caterpillars both in the field and under controlled laboratory conditions. 5. The combined results confirmed that the wasps can size‐select their hosts both in the field and in laboratory tests.     

Determination of the optimal parasitoid‐to‐host ratio for efficient mass‐rearing of the parasitoid,Sclerodermus pupariae (Hymenoptera: Bethylidae)

Sclerodermus pupariae Yang et Yao (Hymenoptera: Bethylidae) is used as a potential biocontrol agent for several buprestid and cerambycid larvae. This study aimed to enhance the efficiency of mass‐rearing of this parasitoid by investigating the fitness gain of this bethylid wasp, including the proportion of successful parasitism and development, brood size, sex ratio, proportion of winged female offspring, body size and longevity of female offspring, under eight different maternal parasitoid density treatments using Thyestilla gebleri Faldermann as host in the laboratory. The results indicated that the foundress densities did not affect the parasitism or emergence rate of this parasitoid. Brood size of the parasitoids increased significantly when the number of maternal wasps ranged from one to four. However, further increases in foundress number did not affect the parasitoid brood size. The sex ratios of S. pupariae were always female‐biased. The proportions of male in the progeny colonies were <10% throughout all experimental treatments. The percentage of winged female progeny was not significantly influenced by the density of adult maternal parasitoids. Body sizes of parasitoids significantly declined with increasing maternal parasitoid densities. Although the parasitoid body size reduced when maternal wasp number was higher, it could be compromised by the relatively higher number of female offspring produced. Further, more than 70% of the parasitoids remained alive when they were stored at 12°C for four months throughout the experiments. These findings suggest that exposure of four female wasps to a single host larva would result in the highest fitness of S. pupariae. Our findings might provide a new approach to enhance the efficiency of mass‐rearing of this bethylid wasp.     

Effects of prey quality on social wasps when given a choice of prey

The effect of prey quality on foraging behavior and colony demographics of the social wasp Polistes fuscatus was examined by providing a choice between non‐toxic prey (Manduca sexta caterpillars) and sublethally toxic prey (Junonia coenia caterpillars), and then comparing the performance of these colonies to others given only the non‐toxic prey. In the choice, one of two types of Manduca were used: those fed an artificial diet or those fed plantain (Plantago lanceolata), which contains iridoid glycosides (IGs) that Junonia coenia store but which Manduca does not. Despite the negative correlation between the number of Junonia prey used and number of adult offspring produced, when a surplus of non‐toxic prey was available, the wasps did not completely avoid the toxic prey. However, they were more discriminating when the choice was between Manduca fed an artificial diet and Junonia fed plantain vs. when both prey species had eaten the plantain. Because the wasps had a choice of prey types and had a surplus of prey on about one‐third of the days, the wasps were able to take enough non‐toxic prey to avoid some of the negative consequences of IGs. For example, the total number of wasp offspring per nest was not affected, but mean weight of female offspring per colony was less for colonies given both prey types eating plantain, compared to that for colonies fed only non‐toxic prey, or those given a choice of non‐toxic prey vs. toxic prey. In addition, compared to the control (only non‐toxic prey), the proportion of males produced was less in the treatment that provided a clear contrast between non‐toxic and toxic prey. Why these wasps did not avoid the toxic prey is discussed.     

DNA barcodes identify 99 per cent of apoid wasp species (Hymenoptera: Ampulicidae,Crabronidae, Sphecidae) from the Western Palearctic

The apoid wasps have traditionally been regarded as a paraphyletic assemblage of four families (Ampulicidae, Crabronidae, Heterogynaidae and Sphecidae) that are closely related to the bees (Anthophila). The present study covers the three families of apoid wasps known to occur in Europe, that is, the Ampulicidae, Crabronidae and Sphecidae. DNA barcode sequences of 3,695 specimens of apoid wasps were analysed for the present study, including 21 specimens of Ampulicidae, 3,398 Crabronidae and 276 Sphecidae. The sequences of the dataset represent 661 species of apoid wasps, including two species of Ampulicidae, 613 of Crabronidae and 46 species of Sphecidae. The dataset includes DNA barcodes of 240 species of German apoid wasps, representing 88% of the German fauna, and 578 European species, representing 65% of the European apoid wasp fauna. The study demonstrates that virtually all species of the three examined families can be reliably identified by DNA barcodes. The implications of highly congruent results between traditional taxonomy and DNA barcoding for the reliable application of DNA‐based identifications are discussed.     

Sexual differences in head form and diet in a population of Mexican lance‐headed rattlesnakes,Crotalus polystictus

Sexual dimorphism of phenotypic traits associated with resource use is common in animals, and may result from niche divergence between sexes. Snakes have become widely used in studies of the ecological basis of sexual dimorphism because they are gape‐limited predators and their head morphology is likely to be a direct indicator of the size and shape of prey consumed. We examined sexual dimorphism of body size and head morphology, as well as sexual differences in diet, in a population of Mexican lance‐headed rattlesnakes, Crotalus polystictus, from the State of México, Mexico. The maximum snout–vent length of males was greater than that of females by 21%. Males had relatively larger heads, and differed from females in head shape after removing the effects of head size. In addition, male rattlesnakes showed positive allometry in head shape: head width was amplified, whereas snout length was truncated with increased head size. By contrast, our data did not provide clear evidence of allometry in head shape of females. Adults of both males and females ate predominately mice and voles; however, males also consumed a greater proportion of larger mammalian species, and fewer small prey species. The differences in diet correspond with dimorphism in head morphology, and provide evidence of intersexual niche divergence in the study population. However, because the sexes overlapped greatly in diet, we hypothesize that diet and head dimorphisms in C. polystictus are likely related to different selection pressures in each sex arising from pre‐existing body size differences rather than from character displacement for reducing intersexual competition. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 633–640.     

A trait‐based approach reveals the feeding selectivity of a small endangered Mediterranean fish

Functional traits are growing in popularity in modern ecology, but feeding studies remain primarily rooted in a taxonomic‐based perspective. However, consumers do not have any reason to select their prey using a taxonomic criterion, and prey assemblages are variable in space and time, which makes taxon‐based studies assemblage‐specific. To illustrate the benefits of the trait‐based approach to assessing food choice, we studied the feeding ecology of the endangered freshwater fish Barbus meridionalis. We hypothesized that B. meridionalis is a selective predator which food choice depends on several prey morphological and behavioral traits, and thus, its top‐down pressure may lead to changes in the functional composition of in‐stream macroinvertebrate communities. Feeding selectivity was inferred by comparing taxonomic and functional composition (13 traits) between ingested and free‐living potential prey using the Jacob's electivity index. Our results showed that the fish diet was influenced by 10 of the 13 traits tested. Barbus meridionalis preferred prey with a potential size of 5–10 mm, with a medium–high drift tendency, and that drift during daylight. Potential prey with no body flexibility, conical shape, concealment traits (presence of nets and/or cases, or patterned coloration), and high aggregation tendency had a low predation risk. Similarly, surface swimmers and interstitial taxa were low vulnerable to predation. Feeding selectivity altered the functional composition of the macroinvertebrate communities. Fish absence favored taxa with weak aggregation tendency, weak flexibility, and a relatively large size (10–20 mm of potential size). Besides, predatory invertebrates may increase in fish absence. In conclusion, our study shows that the incorporation of the trait‐based approach in diet studies is a promising avenue to improve our mechanistic understanding of predator–prey interactions and to help predict the ecological outcomes of predator invasions and extinctions.     

Egg load is a cue for offspring sex ratio adjustment in a fig‐pollinating wasp with male‐eggs‐first sex allocation

Fig‐pollinating wasps (Agaonidae) only reproduce within fig tree inflorescences (figs). Agaonid offspring sex ratios are usually female‐biased and often concur with local mate competition theory (LMC). LMC predicts less female‐bias when several foundresses reproduce in a fig due to reduced relatedness among intra‐sexually competing male offspring. Clutch size, the offspring produced by each foundress, is a strong predictor of agaonid sex ratios and correlates negatively with foundress number. However, clutch size variation can result from several processes including egg load (eggs within a foundress), competition among foundresses and oviposition site limitation, each of which can be used as a sex allocation cue. We introduced into individual Ficus racemosa figs single Ceratosolen fusciceps foundresses and allowed each to oviposit from zero to five hours thus variably reducing their eggs‐loads and then introduced each wasp individually into a second fig. Offspring sex ratio (proportion males) in second figs correlated negatively with clutch size, with males produced even in very small clutches. Ceratosolen fusciceps lay mainly male eggs first and then female eggs. Our results demonstrate that foundresses do not generally lay or attempt to lay a ‘fixed’ number of males, but do ‘reset to zero’ their sex allocation strategy on entering a second fig. With decreasing clutch size, gall failure increased, probably due to reduced pollen. We conclude that C. fusciceps foundresses can use their own egg loads as a cue to facultatively adjust their offspring sex ratios and that foundresses may also produce more ‘insurance’ males when they can predict increasing rates of offspring mortality.     

Effect of host‐cocoon mass on adult size in the secondary hyperparasitoid wasp,Pteromalus semotus (Hymenoptera: Pteromalidae)

Abstract Parasitoids have long proven to be model organisms in studying resource‐related constraints on immature development. Here we examine the relationship between host cocoon (= pupal) size in the gregarious endoparasitoid wasp, Cotesia glomerata, and development time and adult size in the solitary idiobiont hyperparasitoid, Pteromalus semotus. Little is known about the biology or ecology of this ecto‐hyperparasitoid species, although it is one of the major secondary hyperparasitoids of C. glomerata. The size of the adult wasp covaried with the size of the host cocoon at parasitism. Moreover, female wasps were larger than male wasps for a given cocoon size. Adult wasps have remarkably long life‐spans, 3 months on average. Longevity did not significantly differ with sex. We also examined how larvae of P. semotus exclude other potential competitors. P. semotus is protandrous, with females taking significantly longer to complete their development than males. In experiments where several eggs of P. semotus were placed on individual pupae of C. glomerata, newly hatched hyperparasitoid larvae moved rapidly over the surface of the host and destroyed the eggs of any conspecifics by biting them before they would initiate feeding on host tissues. Our results are discussed in relation to those with other studies with solitary ichneumonid idiobiont hyperparasitoids of C. glomerata.     

Does prey mobility affect niche width and individual specialization in hunting wasps? A network‐based analysis

Niche width and inter‐individual diet variation in predator populations are known to be affected by intrinsic factors such as body size, age, cognitive constraints, and by intra‐ and interspecific competition. By contrast, how variation in prey biological traits may affect niche width and partitioning is still a poorly explored topic. One of these candidate traits is prey mobility, which can affect the predators’ niche because acting on the rate of encounter and, assuming mobility as a proxy for escape capability, on the success of predator attacks. Here we analysed 20 wasp populations and their prey as individual‐based food‐webs to test if prey mobility may explain niche width (here defined by the Shannon entropy‐based index ) and patterns of inter‐individual diet variation (here defined by the interaction‐exclusiveness index H₂′ and the interaction evenness index E₂). Niche width was very variable among populations and overall network specialization (H₂′) was always higher than the expected by null models. In case of high‐speed flying prey (e.g. flies, bees), wasps showed wider niches () and lower specialization (H₂′) than in case of non‐flying or slow‐flying prey (e.g. spiders, beetles). Evenness (E₂), on the other side, did not vary with prey mobility. Altogether, these results suggest that highly elusive prey may lead to wider predators’ niche but somehow limit their individual niche specialization.     

Sexual attractiveness shared by both sexes mediates same‐sex sexual behaviour in the parasitoid wasp Telenomus triptus

The mating behaviour of a quasi‐gregarious egg parasitoid Telenomus triptus Nixon (Hymenoptera: Platygastridae), which exploits egg masses of a stink bug Piezodorus hybneri (Heteroptera: Pentatomidae), is examined in the laboratory. In this parasitoid wasp, male adults that emerge earlier stay at the natal egg mass and mate with subsequently emerging females. In the present study, a male adult that encounters the emergence of another male always waits for it to egress, and then mounts the newly emerging male. To examine why males of T. triptus show same‐sex sexual behaviour, male adults are presented with a parasitized host egg mass or a freshly killed wasp. Male adults are observed to remain at host egg masses from which only male wasp(s) had emerged. In addition, male adults attempt to copulate with freshly killed young male wasps. It is suggested that newly emerging male wasps are targets of same‐sex sexual behaviour because they possess cues for male sexual behaviour similar to the cues of females. Both the sex and age of freshly killed wasps affect the frequency of the sexual behaviour of male adults: females are more attractive than males, although their attractiveness declines with age. When the mating opportunity is restricted to the natal egg mass, the costs of failing to notice newly emerging female adults should be extremely high. Therefore, males are forced not to discriminate the sex, resulting in same‐sex sexual behaviour.     

Unique digestive system,trophic specialization,and diversification in the deep‐sea gastropod genus Scaphander

Dietary specialization is known to be important for the evolution of Cephalaspidea gastropods, but still little is known about the overall trophic interactions of the group and the putative role of trophic ecology on diversification. The genus Scaphander is a group of predominantly deep‐sea, infaunal cephalaspids with about 40% of its species (eight) occurring on the Atlantic Ocean. They are carnivorous and have a unique digestive system with a large, strongly muscularized gizzard containing three sizable and heavily calcified plates. This work aims to describe the diet of Scaphander, to evaluate if there is a functional relation between the anatomy of the digestive tract and exploitation of novel food resources, and to assess if dietary specialization may have played a role in the diversification of the Atlantic species of Scaphander. Gut contents were studied from 31 specimens representing seven of the Atlantic species using scanning electron microscopy and light microscopy. The chemical composition of the gizzard plates was analysed by X‐ray microanalysis and X‐ray powder diffraction. Foraminiferans, including agglutinating forms, were shown to be the most important food item for Scaphander; bivalves, gastropods, scaphopods, and polychaetes with calcareous tubes were also found to form part of the diet. The gizzard plates were shown to consist of a phosphate‐rich amorphous component and a crystalline component identified as fluorite (hardness 4; Moh's scale). It is suggested that the ability of Scaphander gastropods to prey upon organisms with hard tests, particularly agglutinating foraminiferans, is not only due to the hardness of the gizzard plates but to the cumulative effect of shape and hardness of the gizzard plates and relative size of the gizzard and associated musculature. No interspecific differences were found in the diet and morphology of the digestive tract, indicating that dietary specialization probably has not played a significant role in the diversification of Atlantic species of Scaphander. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 512–525.     

Hunting behaviour,prey capture and ant avoidance in the tropical social waspPolybia sevicea (Hymenoptera: Vespidae)

Summary Polybia sericea (Hymenoptera: Vespidae) prey foraging was studied by following individual foragers as they hunted in the field, by observing how wasps handled prey once they had captured it, and by observing wasps as they returned to the nest with prey. Wasps were most likely to forage for prey between 0700 and 1300 hours and between 1600 and 1700 hours. The prey foraging sequence consisted of the behaviours high flight, search, touch, land, groom, walk, bite and malaxate. Captured small prey were malaxated and carried to the nest. Wasps removed the gut from large prey and dragged the meat up a twig or grass stem. A load of the meat was then bitten off and malaxated; the remainder was cached while the wasp made an orientation flight and returned to the nest. The forager returned within minutes for the remainder of the prey. Experiments demonstrated that caching the prey remains above the ground rather than close to the ground, where the prey are generally captured, reduces the chance that the prey will be found and expropriated by ants.