Predatory Wasps Research Articles

Agro‐ecosystem services and dis‐services in almond orchards are differentially influenced by the surrounding landscape

1. The simultaneous influence of specific habitats on agro‐ecosystem services, dis‐services, and their interactions are largely unknown. Natural and semi‐natural habitats surrounding cropland may support ecosystem services and dis‐services and their net balance is important to guide decision‐making in agriculture.2. It was tested how natural and semi‐natural habitats surrounding almond orchards in Israel influence: pest control services by parasitoids, pest predation dis‐services by the Almond wasp, and seed predation dis‐services by granivorous birds. The latter could provide sanitation services when consuming almonds infested by Almond wasps after harvest.3. Seventeen almond orchards were surveyed, surrounded by varying percentages of natural and semi‐natural habitats. We harvested almonds to identify Almond wasp infestation and parasitoid abundance, monitored bird‐feeding marks, and observed birds.4. Almond wasp predation was positively influenced by semi‐natural habitat and highest at orchard edges. Parasitoid abundance was not influenced by natural or semi‐natural habitats. Granivorous bird abundance was negatively influenced by semi‐natural habitats but did not influence bird seed predation of harvestable or overwintered almonds.5. Natural habitats did not influence the studied ecosystem services or dis‐services in almond orchards in Israel. Therefore, protecting natural habitats for conservation is not necessarily disadvantageous for farmers. Semi‐natural habitats increased insect pests, but no direct link to services or dis‐services by birds was observed. Therefore, a more holistic approach by accounting for several services and dis‐services and their connection to different habitat types to manage agriculture more sustainably is advocated.

Innovations: New Double Bait Wasp Trap

A double wait wasp is designed and tested for control of predatory wasps attacking honeybee colonies. The trap is effective in capturing wasps and reduces the predatory menace of wasps in apiaries.

Interactions between pygmy bluetongue lizards and co-existing species

This article describes observations of interactions between endangered pygmy bluetongue lizards (Tiliquaadelaidensis) and other species that co-occur in their native grassland habitat in the mid-north region of South Australia. The lizard lives in spider burrows, and rarely moves away from the burrow entrance. We viewed over 16,000 h of video recording of occupied pygmy bluetongue lizard burrows, taken over five 10-day periods throughout one complete lizard activity season, and documented all cases in which these endangered lizards interacted with co-existing species. We found that these interactions were infrequent. We observed potential competition over burrow resources with lycosid spiders (Lycosaspp), centipedes, and a house mouse, and potential competition over invertebrate prey with a predatory wasp. We also observed unsuccessful predation attempts on lizards in burrows by ravens and brown snakes. We suggest that conservation management might have proceeded effectively without this information, but that it provides useful background information for informed decision making.

Statistical comparison of the spatial distribution of both coffee leaf miner and predatory wasps

O cafeeiro esta sujeito ao ataque de pragas que podem causar prejuizos significativos ao produtor. A praga que mais preocupa os cafeicultores brasileiros e o bicho mineiro do cafeeiro (Lepidoptera:Lyonetiidae). Uma maneira de efetuar o controle biologico do bicho mineiro e atraves de vespas predadoras (Hymenoptera: Vespidae). Pesquisadores afirmam que para realizar esse tipo de controle e importante conhecer a distribuicao espacial do bicho mineiro e das vespas. Tambem existem evidencias que a distribuicao espacial dessas especies pode ser influenciada pelas condicoes climaticas. Este trabalho teve por objetivo testar se existe diferenca entre as distribuicoes espaciais de folhas minadas, minas predadas e vespas em diferentes situacoes climaticas. Os dados utilizados foram obtidos no ano de 2006 em um hectare de pantacao de cafe orgânico, situado no municipio de Santo Antonio do Amparo-MG. Para testar a hipotese de igualdade entre duas distribuicoes espaciais foi aplicado o teste de Syrjala. Os resultados obtidos foram: nao houve diferenca na distribuicao espacial de folhas minadas e de minas predadas entre o periodo seco e chuvoso, folhas minadas e vespas apresentaram mesma distribuicao espacial tanto no periodo seco quanto no mes de maior infestacao da praga, as distribuicoes de minas predadas e vespas foram diferentes tanto para o periodo seco quanto para o mes de maior infestacao da praga.

A novel paradigm for nonassociative long-term memory in Drosophila: predator-induced changes in oviposition behavior.

Learning processes in Drosophila have been studied through the use of Pavlovian associative memory tests, and these paradigms have been extremely useful in identifying both genetic factors and neuroanatomical structures that are essential to memory formation. Whether these same genes and brain compartments also contribute to memory formed from nonassociative experiences is not well understood. Exposures to environmental stressors such as predators are known to induce innate behavioral responses and can lead to new memory formation that allows a predator response to persist for days after the predator threat has been removed. Here, we utilize a unique form of nonassociative behavior in Drosophila where female flies detect the presence of endoparasitoid predatory wasps and alter their oviposition behavior to lay eggs in food containing high levels of alcohol. The predator-induced change in fly oviposition preference is maintained for days after wasps are removed, and this persistence in behavior requires a minimum continuous exposure time of 14 hr. Maintenance of this behavior is dependent on multiple long-term memory genes, including orb2, dunce, rutabaga, amnesiac, and Fmr1. Maintenance of the behavior also requires intact synaptic transmission of the mushroom body. Surprisingly, synaptic output from the mushroom body (MB) or the functions of any of these learning and memory genes are not required for the change in behavior when female flies are in constant contact with wasps. This suggests that perception of this predator that leads to an acute change in oviposition behavior is not dependent on the MB or dependent on learning and memory gene functions. Because wasp-induced oviposition behavior can last for days and its maintenance requires a functional MB and the wild-type products of several known learning and memory genes, we suggest that this constitutes a paradigm for a bona fide form of nonassociative long-term memory that is not dependent on associated experiences.

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.

Level of experience modulates individual foraging strategies of an invasive predatory wasp

Spatiotemporal variation in access to resources modulates foraging behavior. Because flexible foraging and subsequent shifting niches can have cascading effects on food webs, it becomes critical to understand what and how information is used during foraging. Yellowjackets are efficient foragers, quickly relocating rewarding resources. Foraging context and the degree of experience were found to affect subsequent behavior and foraging success. An individual forager’s likelihood of relocation was highest for carbohydrates compared to protein and for higher-quality baits. While there was no evidence that odor marking is involved in relocation of sucrose baits, foragers did utilize visual landmarks in the context of protein scavenging. Wasps with limited experience (<4 visits) with a bait responded the most to landmark displacement. However, more experienced wasps avoided misdirection and correctly cued in on the bait. Commensurate with training, a wasp forager visited more often and improved search times at the exact resource location despite displaced landmarks. Successful wasps may detect and associate multiple cues with the training micro-site; such integration of cues could allow the wasps to return to a specific location, even when obvious cues are displaced. Thus, reinforced associative learning likely contributes substantially to foraging patterns and ultimately invasion success, with resource reliability playing a large role. This emphasizes the importance of controlling for experience when comparing foraging across treatments or studies for social wasps.

Physiological selectivity and activity reduction of insecticides by rainfall to predatory wasps of Tuta absoluta

In this study, we carried out three bioassays with nine used insecticides in tomato crops to identify their efficiency against tomato leaf miner Tuta absoluta, the physiological selectivity and the activity reduction of insecticides by three rain regimes to predatory wasps Protonectarina sylveirae and Polybia scutellaris. We assessed the mortality caused by the recommended doses of abamectin, beta-cyfluthrin, cartap, chlorfenapyr, etofenprox, methamidophos, permethrin, phenthoate and spinosad to T. absoluta and wasps at the moment of application. In addition, we evaluated the wasp mortality due to the insecticides for 30 days on plants that did not receive rain and on plants that received 4 or 125 mm of rain. Spinosad, cartap, chlorfenapyr, phenthoate, abamectin and methamidophos caused mortality higher than 90% to T. absoluta, whereas the pyrethroids beta-cyfluthrin, etofenprox and permethrin caused mortality between 8.5% and 46.25%. At the moment of application, all the insecticides were highly toxic to the wasps, causing mortality higher than 80%. In the absence of rain, all the insecticides continued to cause high mortality to the wasps for 30 days after the application. The toxicity of spinosad and methamidophos on both wasp species; beta-cyfluthrin on P. sylveirae and chlorfenapyr and abamectin on P. scutellaris, decreased when the plants received 4 mm of rain. In contrast, the other insecticides only showed reduced toxicity on the wasps when the plants received 125 mm of rain.

Intraspecific Aggression in Giant Honey Bees (Apis dorsata).

We investigated intraspecific aggression in experimental nests (expN1, expN2) of the giant honey bee Apis dorsata in Chitwan (Nepal), focusing on interactions between surface bees and two other groups of bees approaching the nest: (1) homing “nestmate” foragers landing on the bee curtain remained unmolested by guards; and (2) supposed “non-nestmate” bees, which were identified by their erratic flight patterns in front of the nest, such as hovering or sideways scanning and splaying their legs from their body, and were promptly attacked by the surface bees after landing. These supposed non-nestmate bees only occurred immediately before and after migration swarms, which had arrived in close vicinity (and were most likely scouting for a nesting site). In total, 231 of the “nestmate” foragers (fb) and 102 approaches of such purported “non-nestmate” scouts (sc) were analysed (total observation time expN1: 5.43 min) regarding the evocation of shimmering waves (sh). During their landing the “nestmate” foragers provoked less shimmering waves (relnsh[fb] = 23/231 = 0.0996, relnsh[sc] = 75/102 = 0.7353; p <0.001, χ2-test) with shorter duration (Dsh[fb] = 197 ± 17 ms, Dsh[sc] = 488 ± 16 ms; p <0.001; t-test) than “non-nestmates”. Moreover, after having landed on the nest surface, the “non-nestmates” were attacked by the surface bees (expN1, expN2: observation time >18 min) quite similarly to the defensive response against predatory wasps. Hence, the surface members of settled colonies respond differently to individual giant honey bees approaching the nest, depending on whether erratic flight patterns are displayed or not.

Predatory Wasps (Hymenoptera) of the Yucatan Peninsula

Current knowledge regarding predatory wasps (Hymenoptera) of the Yucatan Peninsula, an important region of the Mexican Neotropics, was reviewed. The review includes an overview of the richness of predatory wasps at global, regional, and national levels, as well as revision of pedotrophic and nesting behavior of the species. The review showed the known diversity of species in the Yucatan Peninsula, and that information on pedotrophic and nesting behavior is sparse. To date, 78 species have been recorded in the Yucatan Peninsula. The Family Vespidae has the most species (36) followed by Crabronidae (20), Pompilidae (18), and Sphecidae (four). Most species in the Peninsula were recorded in the state of Yucatan, while few species were recorded in Campeche and Quintana Roo. The pedotrophic behavior of the wasps involves use of some species of insects and caterpillars and spiders. Nests of predatory wasps were most often constructed in the soil or of clay. Further studies are recommended to better understand ecological interactions, as well as the origin and evolution of social behavior and the role wasps play as predators of other arthropods in tropical ecosystems.

Selectivity of Old and New Insecticides and Behaviour of Vespidae Predators in Coffee Crop

Organophosphates are old agrochemicals that are toxic for wasps (Vespidae) that are predators of insect pests. However, chlorantraniliprole is the first insecticide produced from the new anthranilic diamide class, which binds to ryanodine receptor modulators. This study uses chlorpyrifos, triazophos, pyridaphenthion and new chlorantraniliprole insecticides that have not yet been extensively tested for effects on non-target organisms. Adults of the predatory wasps were exposed to concentrations of organophosphate inseticides and the most toxic was used for a behavior test. The trial area, located in the Rio Paranaíba, Minas Gerais, received two treatments: with insecticide and without insecticide. Chlorpyrifos, the most toxic insecticide, was used in the dose of 1.5L/ha. In order to evaluate the predation, the number with predation action (injuries made by the wasps) in the leaves were accounted. Behavior activities collect of nine colonies Protonectarina sylveirae, Brachigastra lecheguana, Polybia sp. and Polistes versicolor works were quantified. All colonies were in the adult phase. The colonies were observed by 12h, from 6:00 a.m. to 6:00 p.m. The number of wasps that leaved and returned to the nest, type of sources collected (glucidic foods, prey larvae, matherial for construction of the nest). The most toxic insecticide was chlorpyrifos and the most selective was chlorantraniliprole. The species and frequencies of wasps predator were: P. sylveirae (71.50%), B. lecheguana (12.00%), Polybia sp. (7.00%) and P. versicolor (1.00%). Chlor-pyrifos presented not selective and changes in the behavior to the predatory wasps.

Innovative Method for Safety of Bees at Hive Entrance from Predatory Wasps (Hymenoptera: Vespidae)

Innovative Method for Safety of Bees at Hive Entrance from Predatory Wasps (Hymenoptera: Vespidae)

How to be an ant on figs

Mutualistic interactions are open to exploitation by one or other of the partners and a diversity of other organisms, and hence are best understood as being embedded in a complex network of biotic interactions. Figs participate in an obligate mutualism in that figs are dependent on agaonid fig wasps for pollination and the wasps are dependent on fig ovules for brood sites. Ants are common insect predators and abundant in tropical forests. Ants have been recorded on approximately 11% of fig species, including all six subgenera, and often affect the fig–fig pollinator interaction through their predation of either pollinating and parasitic wasps. On monoecious figs, ants are often associated with hemipterans, whereas in dioecious figs ants predominantly prey on fig wasps. A few fig species are true myrmecophytes, with domatia or food rewards for ants, and in at least one species this is linked to predation of parasitic fig wasps. Ants also play a role in dispersal of fig seeds and may be particularly important for hemi-epiphytic species, which require high quality establishment microsites in the canopy. The intersection between the fig–fig pollinator and ant–plant systems promises to provide fertile ground for understanding mutualistic interactions within the context of complex interaction networks.

Ants have a negative rather than a positive effect on extrafloral nectaried Crotalaria pallida performance

Crotalaria pallida (Fabaceae) is a pantropical plant with extrafloral nectaries (EFNs) near the reproductive structures. EFN-visiting ants attack and remove arctiid moth Utetheisa ornatrix larvae, the main pre-dispersal seed predator, but the impact of ants on C. pallida fitness is unknown. To assess this impact, we controlled ant presence on plants and evaluated the reproductive output of C. pallida with and without ants. Predatory wasps also visit EFNs, prey upon U. ornatrix larvae, and may be driven out by ants during EFN feeding. Does this agonistic interaction affect the multitrophic interaction outcome? We found it difficult to evaluate the effect of both visitors because cages excluding wasps affect plant growth and do not allow U. ornatrix oviposition. Therefore, we verified whether ant presence inhibited wasp EFN visitation and predicted that (1) if ants confer a benefit for C. pallida, any negative effect of ants on wasps would be negligible for the plant because ants would be the best guardians, and (2) if ants are poor guardians, they would negatively affect wasps and negatively impact the fitness of C. pallida. Surprisingly, we found that the number of seeds/pods significantly increased, ca. 4.7 times, after ant removal. Additionally, we unexpectedly verified that controls showed a higher percentage of herbivore bored pods than ant-excluded plants. We found that wasps spent less time visiting EFNs patrolled by ants (ca. 299 s less). These results support our second prediction and suggest that the outcome of multitrophic interactions may vary with natural enemy actors.

Weak defence in a tritrophic system: olfactory response to salicylaldehyde reflects prey specialization of potter wasps

Predatory arthropods are attracted to infochemicals emitted by their herbivore prey or by the prey’s host plants. We studied such a tritrophic system measuring the olfactory responses of three potter wasp species (Symmorphusmurarius, Symmorphusgracilis, Discoeliuszonalis, Hymenoptera: Eumeninae) to salicylaldehyde, sequestered as a defence compound by Chrysomela leaf beetle larvae when feeding on Salicaceae, and volatile organic compounds (VOCs) emitted by aspen (Populus tremula, Salicaceae). In electroantennographic recordings (EAG), the highly specialized S. murarius that almost exclusively feeds on larvae of Salicaceae-feeding Chrysomela species was more sensitive to salicylaldehyde than the less specialized S.gracilis, feeding on such Chrysomela species but also weevil larvae. In contrast the related D. zonalis, foraging for microlepidoptera caterpillars on various host plants, did not respond at all. Furthermore, the three wasp species responded differently to aspen VOCs in GC–MS/EAD measurements. These results indicate that the sense of smell of predatory potter wasps differs for prey and plant volatiles among related wasp species according to their degree of host specialization. The considerable differences in salicylaldehyde perception suggest that its originally defensive function has backfired as it is used by specialist potter wasps for prey location. This is an important clue on adaptive mechanisms of the highest trophic level of the well-studied evolutionary arms race among Chrysomela leaf beetles, their host plants and their enemies.

Three-dimensional barricading of a predatory trap reduces predation and enhances prey capture

Animal structures come at material, energetic, time, and expression costs. Some orb-web spiders add three-dimensional barrier structures to their webs, but many do not. Predator protection is considered to be the principal benefit of adding these structures. Accordingly, it remains paradoxical why some orb-web spiders might construct the barriers while others do not. Here, we experimentally determined whether the barrier structure added to the horizontal orb web of the spider Cyrtophora moluccensis deters predators at the cost of reducing the amount of prey captured in the field. We conducted experiments by day and night to assess whether the effects vary with the time of day. We found that the three-dimensional barriers not only offered protection from predatory wasps by day but also enhanced the amount of prey captured by day and night. Moreover, the barrier structure appears particularly useful at catching moths, the largest and most energetically profitable prey that it encounters. We, therefore, concluded that reducing the energetic and time costs associated with producing and depositing extra silk threads is the principal reason why barrier structures are used intermittently among orb-web spiders.

Sexual size dimorphism in the ontogeny of the solitary predatory wasp Symmorphus allobrogus (Hymenoptera: Vespidae)

Sex-specific patterns of individual growth, resulting in sexual size dimorphism (SSD), are a little studied aspect of the ontogeny related to the evolutionary history and affected by the ecology of a species. We used empirical data on the development of the predatory wasp Symmorphus allobrogus (Hymenoptera, Vespidae) to test the hypotheses that sexual differences of growth resulting in the female-biased SSD embrace the difference in (1) the egg size and the starting size of larva, (2) the larval development duration, and (3) the larval growth rate. We found that eggs developing into males and females have significant differences in size. There was no significant difference between the sexes in the duration of larval development. The relative growth rate and the food assimilation efficiency of female larvae were significantly higher than compared to those of male larvae. Thus, the SSD of S. allobrogus is mediated mainly by sexual differences in egg size and larval growth rate.

Foraging behavior of Brachygastra lecheguana (Hymenoptera: Vespidae) on Banisteriopsis malifolia (Malpighiaceae): Extrafloral nectar consumption and herbivore predation in a tending ant system

AbstractIn the Brazilian savanna many plant species bear regular associations with patrolling ants that are aggressive towards insect herbivores. However, not only ants but also several species of predatory wasps are attracted to plants due to the extrafloral nectaries (EFNs). Such wasps feed on both herbivores and plant exudates. In this study we describe the foraging behavior of the social Polistinae wasp Brachygastra lecheguana in the extrafloral nectaried shrub Banisteriopsis malifolia, and investigated the influence of patrolling ants Camponotus blandus on the activity of the wasp. Brachygastra lecheguana fed on the endophytic larvae of Anthonomus (Curculionidae) beetles that developed inside flower buds. The wasp lacerated the bud layers to reach the beetle larvae located at the bud core. The wasp visits to Ba. malifolia were statistically related to the abundance of flower buds and beetles. Ant exclusion experiments revealed that the hunting behavior of B. lecheguana on beetles was not related to the absence of C. blandus. However we found that wasps spent more time consuming extrafloral nectar on branches where ants were excluded. This is the first study reporting extrafloral nectar consumption by B. lecheguana, as well as the predation on herbivores in natural areas. In cerrado vegetation, ants benefit the plant by reducing insect herbivores, and our study provides evidence that the B. lecheguana – Ba. malifolia system represents a potential interaction where the wasp may also benefit the host plant. The value of this wasp species as a plant‐guard is discussed.

Identifying the sister group to the bees: a molecular phylogeny of Aculeata with an emphasis on the superfamily Apoidea

Debevec, AH., Cardinal, S &amp; Danforth, BN. Identifying the sister group to the bees: a molecular phylogeny of Aculeata with an emphasis on the superfamily Apoidea. —Zoologica Scripta, 41, 527–535.The hymenopteran superfamily Apoidea includes the bees (Anthophila) as well as four predatory wasp families (Heterogynaidae, Ampulicidae, Sphecidae and Crabronidae) collectively referred to as the “sphecoid” or “apoid” wasps. The most widely cited studies suggest that bees are sister to the wasp family Crabronidae, but alternative hypotheses have been proposed based on both morphological and molecular data. We combined DNA sequence data from previously published studies and newly generated data for four nuclear genes (28S, long‐wavelength rhodopsin, elongation factor‐1α and wingless) to identify the likely sister group to the bees. Analysis of our four‐gene data set by maximum likelihood and Bayesian methods indicates that bees most likely arise from within a paraphyletic Crabronidae. Possible sister groups to the bees include Philanthinae, Pemphredoninae or Philanthinae + Pemphredoninae. We used Bayesian methods to explore the robustness of our results. Bayes Factor tests strongly rejected the hypotheses of crabronid monophyly as well as placement of Heterogynaidae within Crabronidae. Our results were also stable to alternative rootings of the bees. These findings provide additional support for the hypothesis that bees arise from within Crabronidae, rather than being sister to Crabronidae, thus altering our understanding of bee ancestry and evolutionary history.

Seasonal variation of natural mortality factors of the guava psyllidTriozoida limbata

It is important to understand how components of the agroecosystem interfere with the attack of a pest species and their seasonality in order to use these components in IPM programs. This study focused on the evaluation of the seasonality of natural control factors associated with the guava psyllid Triozoida limbata (Enderlein) in Brazil. Life-table data were collected from an experimental guava orchard during four periods that roughly represented four seasons. Natural mortality was monitored daily through the immature stages, and the relative importance of each natural mortality factor and its seasonality was determined. Significant statistical differences were observed in the mortality during the four periods (P < 0.05). Several factors contributed to the mortality of T. limbata, including rainfall, physiological disturbance, the parasitoid Psyllaephagus sp. (Hymenoptera: Encyrtidae) and specific predators: syrphids, predatory wasps and other generalist predators. Depending on the location of nymphs (exposed or inside galls), the relative importance of the different natural mortality factors changed. The principal component analysis (PCA) showed some trends in the relationship of natural control agents and weather conditions. For example, the occurrence of predatory wasps was positively correlated with temperature and occurrence of winds; the occurrence of syrphids and Psyllaephagus sp. were negatively correlated with temperature and winds; and the occurrence of other generalist predators were negatively correlated with the occurrence of rainfall and photoperiod. The results showed the importance of natural mortality factors for the management of T. limbata and their changes through the different seasons which should be considered when implementing IPM programs in guava orchards.