Behavior Of Wasps Research Articles

Antennal sensilla in the parasitoid Sclerodermus sp. (Hymenoptera: Bethylidae).

Parasitoid wasps of the genus Sclerodermus (Hymenoptera: Bethylidae) are an important natural enemy of the Japanese pine sawyer beetle Monochamus alternatus Hope (Coleoptera: Cerambycidae). In this study, we used scanning electron microscopy to examine the external morphology of the antennal sensilla of Sclerodermus sp. Antennae of females and males comprised the scape, pedicel, and 11 flagellomere segments. Based on the morphology of the sensilla in each sex, seven types of sensillum were identified: sensilla trichodea (Tr.1, Tr.2 and Tr.3), sensilla basiconica (Ba.1, Ba.2, and Ba.3), sensilla styloconica (St.1 and St.2), sensilla placodea, sensilla coeloconica, sensilla squamiforma, and Bohm’s bristles. Tr.2, Ba.1, and St.1 were only found in females, whereas Ba.2, Ba.3, and St.2 were only observed in males. Sensilla placodea were the most common, given that they occur on the antennae of many parasitoid Hymenoptera, whereas sensilla Tr were the most abundant, being distributed over the entire antennal surface. These sensilla are likely to have roles in the host locating and habitat searching behavior of adult Sclerodermus wasps. Therefore, our findings provide a basis for further studies of the host location behavior of this and other species of parasitic wasp.

Does Wolbachia infection affect decision‐making in a parasitic wasp?

AbstractVarious physiological effects of Wolbachia infection have been reported in invertebrates, but the impact of this infection on behavior and the consequences of these behavioral modifications on fitness have rarely been studied. Here, we investigate the effect of Wolbachia infection on the estimation of host nutritive resource quality in a parasitoid wasp. We compare decision‐making in uninfected and Wolbachia‐infected strains of Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) on patches containing either fresh or old host eggs. For both strains, fresh eggs were better hosts than older eggs, but the difference was smaller for the infected strain than for the uninfected strain. Oviposition behavior of uninfected wasps followed the predictions of optimal foraging theory. They behaved differently toward high‐ vs. low‐quality hosts, with more hosts visited and more ovipositions, fewer high‐quality hosts used for feeding or superparasitism, and a sex ratio that was more biased toward females in patches containing high‐quality hosts than in patches containing low‐quality ones. Uninfected wasps also displayed shorter acceptance and rejection times in high‐quality hosts than in hosts of lower quality. In contrast, infected wasps were less efficient in evaluating the nutritive quality of the host (fresh vs. old eggs) and had a reduced ability to discriminate between unparasitized and parasitized hosts. Furthermore, they needed more energy and therefore engaged in host feeding more often. This study highlights possible decision‐making manipulation by Wolbachia, and we discuss its consequences for Wolbachia fitness.

Pollen Wasps and Flowers in Southern Africa and Wasps and Bees in Southern AfricaPollen Wasps and Flowers in Southern Africa by S.K. Gess & F.W. Gess . SANBI Biodiversity Series 18. South African National Biodiversity Institute, Pretoria. 2010. 147 pp. Price R160 (paperback). ISBN 978-1-919976-60-0.Wasps and Bees in Southern Africa by S.K. Gess & F.W. Gess . SANBI Biodiversity Series

A formidable team, Sarah and Fred Gess spent in excess of 40 years patiently observing the lives of wasps and bees on numerous extended field trips, mostly into the more arid western areas of southern Africa. Their passion for insects, combined with careful observation and dedicated documentation of data facilitated the elucidation of the intricate nature of the ecology and behaviour of Africa's wasps and bees. With their complementary expertise and skills, Fred and Sarah compiled a comprehensive knowledge base that will serve the scientific and conservation communities well into the future. The culminated data are now available in two excellent SANBI publications, both richly illustrated with colour photographs and containing a wealth of biological information, providing valuable baseline data for future conservation assessments.

Behavioural response of the woodwasp Sirex noctilio to volatile emissions of its fungal symbiont

AbstractThe wood‐boring wasp, Sirex noctilio, is a global invasive pest that infects and kills pine trees by inoculating spores of a symbiotic fungus (Amylostereum areolatum) at oviposition. Wasp larvae depend on fungal growth to feed, while the fungus relies on female wasps to initially condition the pine tree by inoculating a phytotoxic venom and for dispersal. Wasp larvae use the fungus as an external gut for the digestion of lignocellulosic compounds resulting in a strong correlation between fungal growth inside the wood and wasp fitness. This study explores the hypothesis that female wasps will use fungal volatiles as a synomone in the process of locating suitable oviposition areas (i.e. trees). Using a Y‐tube olfactometer, adult female wasp behaviour was assessed towards fungal and pine tree volatiles (i.e. positive control). Our results are the first to demonstrate attraction of female S. noctilio towards volatiles of their fungal symbiont. Furthermore, the positive response towards these volatiles seems to be stronger than the response to a known attractant (i.e. pine volatiles). These results could be an important contribution to improving baits for monitoring and control purposes. Further work is needed, mainly oriented towards the identification of the volatiles that trigger the observed attraction response and their possible synergistic effects with tree volatiles.

Escape-hatching responses of individual treefrog embryos vary with threat level in wasp attacks: a mechanistic analysis

Theory predicts that prey behavioural responses should reflect the level of risk posed by predators. We investigated how red-eyed treefrog embryos perceive and respond to spatially variable risk during wasp attacks on their clutches. First, we spatially restricted wasp activity on clutches and compared hatching of wasp-exposed, adjacent, and protected embryos. Hatching occurred in all zones but increased with exposure, being highest in directly exposed embryos. Second, we videotaped wasps attacking clutches and compared the experiences of embryos that hatched first and those that did not hatch until later. Embryos that hatched first experienced more predatory wasp activity directed at themselves or at siblings within a 2-egg radius. Models predicting hatching indicate that cues used to assess risk originate from the behaviour of wasps, rather than other embryos. This research demonstrates that embryos can integrate information about predator behaviour and proximity to respond appropriately based on their level of risk.

Host Approaching Behavior in a Parasitoid Wasp (Hymenoptera: Ichneumonidae) as Influenced by Physiological State and Host Type

The present study highlighted the interactions of host type and physiological state (i.e., the number of mature eggs a female carries) in determining a parasitoid’s host-finding behavior, using the solitary endoparasitoid Itoplectis naranyae (Hymenoptera: Ichneumonidae). Females took much shorter time to approach and attack healthy hosts of high-value than empty hosts of no-value, discriminating between the host types from a short distance. Variance of the time was much greater for empty hosts. A striking difference was detected in the influence of physiological state on wasp behavior; females with greater egg loads approached an empty host more quickly in order to examine its suitability for oviposition whereas egg load effects were not found for healthy hosts. Thus, egg load was involved in variation of the host-finding behavior but its effects depended on host types. We discuss the adaptive significance of the context dependent effects of egg load on parasitoid behavior

AN EXPERIMENTAL COLLECTIVE INTELLIGENCE RESEARCH TOOL

The Collective Intelligence Research Tool (CIRT) is an experimental software and hardware research tool. It provides an inexpensive and efficient alternative research implementation that demonstrates simulations of the collective behavior of self-organized systems, primarily social insects. The software focuses on 2D simulations of the woodchip-collecting behavior of termites and 3D simulations of the building behavior of wasps. The hardware simulation employs a Boe-Bot robot, which has the potential of simulating simple movements of a social insect, by extending its functionality through adding sensors and integrating a control chip.

Inexplicably female-biased sex ratios in Melittobia wasps.

The sex ratio behavior of parasitoid wasps in the genus Melittobia is scandalous. In contrast to the prediction of Hamilton's local mate competition theory, and the behavior of numerous other species, their extremely female-biased sex ratios (1-5% males) change little in response to the number of females that lay eggs on a patch. We examined the mating structure and fitness consequences of adjusting the sex ratio in M. australica and found that (1) the rate of inbreeding did not differ from that expected with random mating within each patch; (2) the fitness of females that produced less female-biased sex ratios (10 or 20% males) was greater than that of females who produced the sex ratio normally observed in M. australica. These results suggest that neither assortative mating nor asymmetrical competition between males can explain the extreme sex ratios. More generally, the finding that the sex ratios produced by females led to a decrease in their fitness suggests that the existing theory fails to capture a key aspect of the natural history of Melittobia, and emphasizes the importance of examining the fitness consequences of different sex ratio strategies, not only whether observed sex ratios correlate with theoretical predictions.

Temporal Activity Patterns and Foraging Behavior by Social Wasps (Hymenoptera, Polistinae) on Fruits of Mangifera indica L. (Anacardiaceae)

This research was done in Juiz de Fora, Minas Gerais, Brazil on february 2012, with objective was to determine which species of social wasps visiting mango fruits, their behaviors displayed by them while foraging and verify which the species of wasps visitors offer risk of accidents to farmers. The studied area was monitored during February 2012, from 8:00 to 17:00. in a 144 hour effort, and the data collected included the time of activity, diversity, aggressiveness and the general behavior of social wasps around the fruits. There were registered a total of 175 individuals of 12 different species, healthy fruits were damaged during the day, and we registered the abundance and richness peaks throughout the day. This study indicated the needs for special care during the harvest, as aggressive wasps are indeed present and the abundant, resulting in a possible increase of the risk for the workers.

Males of Neotropical social wasps (Vespidae, Polistinae, Epiponini) recognize colonies with virgin females

Male behavior of Neotropical swarm-founding wasps has rarely been observed. The few published observations about male activities only describe their behavior during the short period they spend inside nests. In consequence, virtually nothing is known about what they do outside the colonies, and even less is known about mating behavior. This paper provides the first report of Epiponini males arriving at a colony with virgin females. The behavior of males and workers after queen removal was observed in one colony of Chartergellus communis located at a farm in Pedregulho, Sao Paulo, Brazil. The day after queen elimination, males were observed outside the nest. When males tried to enter the nest, workers aggressively attacked them. These attacks were similar to the defensive behavior used when foreign conspecifics attempt to enter the nest. The aggressive workers response and the absence of males before queen removal indicated that the males did not belong to the colony. Additionally, no fights were observed between individuals before queen removal. It is likely that foreign males arrived at the colony to mate with virgin females. Observations suggest that epiponine males are able to find nests with virgin females in mature stages of the colony cycle, and that mating can occur during different stages of the colony cycle.

A trophic cascade induced by predatory ants in a fig–fig wasp mutualism

A trophic cascade occurs when predators directly decrease the densities, or change the behaviour, of herbivores and thus indirectly increase plant productivity. The predator-herbivore-plant context is well known, but some predators attack species beneficial to plants (e.g. pollinators) and/or enemies of herbivores (e.g. parasites), and their role in the dynamics of mutualisms remains largely unexplored. We surveyed the predatory ant species and studied predation by the dominant ant species, the weaver ant Oecophylla smaragdina, associated with the fig tree Ficus racemosa in southwest China. We then tested the effects of weaver ants on the oviposition behaviour of pollinating and non-pollinating fig wasps in an ant-exclusion experiment. The effects of weaver ants on fig wasp community structure and fig seed production were then compared between trees with and without O.smaragdina. Oecophylla smaragdina captured more non-pollinating wasps (Platyneura mayri) than pollinators as the insects arrived to lay eggs. When ants were excluded, more non-pollinators laid eggs into figs and fewer pollinators entered figs. Furthermore, trees with O.smaragdina produced more pollinator offspring and fewer non-pollinator offspring, shifting the community structure significantly. In addition, F.racemosa produced significantly more seeds on trees inhabited by weaver ants. Oecophylla smaragdina predation reverses the dominance of the two commonest wasp species at the egg-laying stage and favours the pollinators. This behavioural pattern is mirrored by wasp offspring production, with pollinators' offspring dominating figs produced by trees inhabited by weaver ants, and offspring of the non-pollinator P.mayri most abundant in figs on trees inhabited by other ants. Overall, our results suggest that predation by weaver ants limits the success of the non-pollinating P.mayri and therefore indirectly benefits the mutualism by increasing the reproductive success of both the pollinators and the plant. Predation is thus a key functional factor that can shape the community structure of a pollinator-plant mutualistic system.

Chemical Ecology: Body Odor, Behavior, and Body Building

Chemical Ecology: Body Odor, Behavior, and Body Building

In memoriam: Dr. J. (Hans) van den Assem

On 11 April 2014 behavioral biologist Hans van den Assem passed away. As member of the Ethology group at the University of Leiden he has contributed significantly to the blossoming of the field of behavioral biology. Hans was a pioneer in the study of mating behavior of parasitoid wasps, contributed to the development of Nasonia as a hymenopteran model organism, and was among the first to show that parasitoids can adaptively adjust their progeny sex ratios. He has been an inspiring mentor and is best remembered as a “scholar and gentleman”.

Strike Fast, Strike Hard: The Red-Throated Caracara Exploits Absconding Behavior of Social Wasps during Nest Predation

Red-throated Caracaras Ibycter americanus (Falconidae) are specialist predators of social wasps in the Neotropics. It had been proposed that these caracaras possess chemical repellents that allow them to take the brood of wasp nests without being attacked by worker wasps. To determine how caracaras exploit nests of social wasps and whether chemical repellents facilitate predation, we: (1) video recorded the birds attacking wasp nests; (2) analyzed surface extracts of the birds' faces, feet, and feathers for potential chemical repellents; and (3) inflicted mechanical damage on wasp nests to determine the defensive behavior of wasps in response to varying levels of disturbance. During caracara predation events, two species of large-bodied wasps mounted stinging attacks on caracaras, whereas three smaller-bodied wasp species did not. The “hit-and-run” predation tactic of caracaras when they attacked nests of large and aggressive wasps reduced the risk of getting stung. Our data reveal that the predation strategy of caracaras is based on mechanical disturbance of, and damage to, target wasp nests. Caracara attacks and severe experimental disturbance of nests invariably caused wasps to abscond (abandon their nests). Two compounds in caracara foot extracts [sulcatone and iridodial] elicited electrophysiological responses from wasp antennae, and were also present in defensive secretions of sympatric arboreal-nesting Azteca ants. These compounds appear not to be wasp repellents but to be acquired coincidentally by caracaras when they perch on trees inhabited with Azteca ants. We conclude that caracara predation success does not depend on wasp repellents but relies on the absconding response that is typical of swarm-founding polistine wasps. Our study highlights the potential importance of vertebrate predators in the ecology and evolution of social wasps.

Available kin recognition cues may explain why wasp behavior reflects relatedness to nest mates

Relatedness is predicted to be a key determinant of cooperative behavior, but kin discrimination within social insect colonies is surprisingly rare. A lack of reliable cuticular hydrocarbon (CHC) cues is thought to be responsible, but here we show that in a high-profile paper wasp model, kin recognition cues are available for some individuals that found nests with nonrelatives. Thus, unrelated Polistes dominulus helpers could potentially recognize themselves as such. On this basis, we reanalyzed a behavioral data set to investigate whether foraging effort, defense contributions and aggression toward nest mates might thus reflect CHC profiles. Both foraging behavior and aggression varied with genetic relatedness, but genetic relatedness itself was a better predictor of this variation than differences in CHC profiles. We propose that wasps use specific components of the CHC profile, the identity of which is as yet unknown, to identify relatives among nest mates. Our data provide the first evidence of within-nest kin discrimination in primitively eusocial wasps but leave open the question of which cues are responsible.

Social Wasps on Eugenia uniflora Linnaeus (Myrtaceae) Plants in the Urban Area of Viçosa, Minas Gerais State, Brazil

Social wasps (Hymenoptera: Vespidae) of the subfamily Polistinae, being biological pest control agents, can effectively participate in ongoing efforts to limit the use of chemical agents used in combating insect pests in urban forestry. The objective of the study, conducted in Viçosa, Minas Gerais State, Brazil, in May 2011, was aimed at identifying species of this group foraging on Eugenia uniflora Linnaeus (Myrtaceae) plants. The study area was monitored once a week, even as data on social wasps foraging on plants of E. uniflora were collected. The data collected included study of their daily activity pattern, diversity, dominance and overlap of temporal niches relating to species of this group. Data analysis revealed that E. uniflora plants were visited by 217 individuals of 16 species of the subfamily Polistinae. Foraging behavior of social wasps bore no relationship with sampling time, but overlap of temporal niche was high. It was observed that the species of social wasps did not damage healthy fruits, but they were probably searching for Lonchaeidae and Tephritidae larvae. It is important to preserve the diversity of these predators, since they are potentially important as a partial alternative to environmentally degrading chemical pesticides currently used in urban forestry for pest control.

Group hunting by workers of two Neotropical swarm-founding paper wasps, Parachartergus apicalis and Agelaia sp.

Here we report field observations of group hunting by two Neotropical species of paper wasps, Para- chartergus apicalis in Costa Rica and Agelaia cf. angulata in Peru. In both cases, multiple workers simultaneously attacked live caterpillar prey. We describe the wasps' behavior and their interactions with the relatively large- bodied ((80 mm length) caterpillars, and we discuss the implications of these observations for paper wasp behavior and ecology.

Mate-Searching Behaviour of Common and Rare Wasps and the Implications for Pollen Movement of the Sexually Deceptive Orchids They Pollinate

Pollinator behaviour directly affects patterns of pollen movement and outcrossing rates in plants. In orchids pollinated by sexual deception of insects, patterns of pollen movement are primarily determined by the mate-searching behaviour of the deceived males. Here, using a capture-mark-recapture study (CMR) and dietary analysis, we compare mate-searching behaviour in relation to local abundance of two pollinator species and explore the implications for pollen movement in sexually deceptive Drakaea (Orchidaceae). Drakaea are pollinated solely by the sexual deception of male thynnine wasps. The rare Drakaea elastica and widespread D. livida occur sympatrically and are pollinated by the rare but locally common Zaspilothynnus gilesi, and the widespread and abundant Z. nigripes, respectively. Local abundance was significantly different with Z. nigripes twice as abundant as Z. gilesi. For the 653 marked wasps, there was no significant difference in median movement distance between Z. gilesi and Z. nigripes. However, the maximum movement distance was twice as high for Z. gilesi (556 m) compared with Z. nigripes (267 m). This is up to three times greater than previously reported for thynnines in CMR studies. Recapture rates were six times higher in Z. gilesi (57%) compared to Z. nigripes (9%). Pollen loads and wasp longevity were similar, suggesting that this difference in recapture rate arises due to differences in the number of males moving at a scale >500 m rather than through diet or mortality. Differences in the frequency of longer movements may arise due to variation in the spatial distribution of the wingless females. We predict that pollen movement will largely be restricted to within populations of Drakaea (<500 m), with few movements between populations (>500 m).

Nest Architectural Patterns by Three Wasp Species (Vespa velutina, Polistes flavus and Sceliphron formosum) with Reference to Their Behavior.

In the present study, the nest architectural patterns, elemental analysis and their behavior were carried out in three wasp species: Vespa velutina (Lepeletier), Polistes flavus (Cresson) and Sceliphron formosum (Smith) from the different localities of the Mansehra, Pakistan. The V. velutina nest was completely closed except for one opening for entry or exit with 1–10 layers of hexagonal cells inside the nest. The nests of P. flavus were found among bunches of leaves of trees with 1–5 layers and hexagonal cells same as in V. velutina. Nests of the S. formosum were pitcher-shaped, found in muddy places, and consisted of 1–10 cells. Social behavior of wasps showed strong foraging, defensive behaviors, pseudo-attack, subsequent erratic flight, wing buzzing, mandibular pecking, abdominal pumping and abdominal twisting with highly developed parental care. It was concluded that the behaviors of these 3 wasp species was highly developed as compared with other insects.

Intra-Population Genetic Variation in the Temporal Pattern of Egg Maturation in a Parasitoid Wasp

Parasitoid wasps are taxonomically and biologically extremely diverse. A conceptual framework has recently been developed for understanding life-history evolution and diversification in these animals, and it has confirmed that each of two linked life-history traits – the mode of larval development and the temporal pattern of egg maturation – acts as an organiser of life-history. The framework has been predicated on the assumption that there exists sufficient genetic variation in the latter trait to allow it to be shaped by natural selection. Focusing on the parasitoid wasp Trichogramma brassicae, our aim was to test the validity of that assumption, using established quantitative genetic methods. We demonstrate the existence of a statistically significant degree of intra-population polygenic variation in the temporal pattern of egg production within the wasp population we studied. Furthermore, our results, together with published data on clinal variation in the egg maturation pattern of another species, suggest that intra-specific evolutionary shifts in the temporal pattern of egg maturation of parasitoid wasps can result from a change in allocation to egg production either before, or very shortly after adult emergence, without there being an accompanying change in lifetime fecundity. As well as opening new avenues of research into the reproductive strategies, behaviour, community organisation and biological control potential of parasitoid wasps, this discovery also has implications for studies of life-history evolution and diversification in insects generally.