Agelaia pallipes is a species of social paper wasp found from Costa Rica to Brazil, Argentina and Paraguay. A. pallipes is ground-nesting and is one of the most aggressive wasps in South America. This species is a predator of other insects, including flies, moths, and ground crickets, as well as baby birds.
Taxonomy and phylogeny
A. pallipes is part of the family Vespidae, subfamily Polistinae, tribe Epiponini, and subsequently the genus Agelaia. Vespidae is characterized by the eusociality of its members. Eusociality refers to the complex organization of animal behavior and is defined by these four attributes: adults live in groups, cooperative care of juveniles, reproductive division of labor where only specific members have the capacity to reproduce, and an overlap of generations.Plowes, N. (2010) An Introduction to Eusociality. Nature Education Knowledge 3(10):7 In Polistinae, prey and other food resources are masticated and fed to larvae, who in turn give back a clear but nutritious liquid which the adults then consume. The Epopini is a tribe of Polistinae characterized by being polygynic, with many queens and reproduction in swarms.Noll, F, et al. 2004. Evolution of Caste in Neotropical Swarm-Founding Wasps (Hymenoptera: Vespidae; Epiponini). American Museum Novitates.
Relatives of A. pallipes in the Agelaia genus include: A. vicina, A. flavipennis, A. areata, A. angulicollis, A. cajennensis, A. fulvofasciata, A. myrmecophila, A. yepocapa, and A. panamaensis.
Description Depending on their location and altitude, A. pallipes can vary from in length and are yellow with black maculation. Their head displays a range of colors of black, yellow and brown. Their bodily terga vary from yellow to brown and black. Their legs and wings are also yellow.Hermes, Marcel Gustavo and Kohler, Andreas. The genus Agelaia Lepeletier (Hymenoptera, Vespidae, Polistinae) in Rio Grande do Sul, Brazil. Rev. Bras. entomol.[online]. 2004, vol.48, n.1 [cited 2014-09-25], pp. 135-138 There is clear dimorphism between queens (egg-layers) and sterile female workers with the former displaying physical superiority and size in 17 of 22 characteristics relating to the head, mesosoma, metasoma and wings.Noll, F.B., D. Simões & R. Zucchi. 1997. Morphological caste differences in Neotropical swarm-founding Polistinae wasps. Agelaia m. multipicta and A. p. pallipes (Hymenoptera: Vespidae). Ethol. Ecol. Evol. 9: 361-372. There is also clear dimorphism between ovary development of the two different castes of females. Longer and developed ovaries are seen in queens whereas short, thread-like ovaries are seen in workers. There is a stark absence of no transitional females (workers with developed ovaries) thus showing unambiguous division between castes. Furthermore, what separates workers from queens is the presence of a brown or black stripe on the humeri.
Their nests are composed of vertical combs made of horizontal combs forming a single form row of concentric hemispheres.Richards O.W. 1978. The social wasps of the Americas excluding the Vespinae. London: British Museum. 580pp. Found in ground cavities, their nests are found to have a maximum diameter of with a maximum of 16,500 individuals.Rodríguez-Jimenez, Andrea, & Sarmiento, Carlos E.. (2008). Altitudinal distribution and body resource allocation in a High Mountain social wasp (Hymenoptera: Vespidae). Neotropical Entomology, 37(1), 1-7.
Distribution and habitat
Being a species of tropical distribution, A. pallipes is found in the central and northern regions of South America and is commonly restricted to the high-altitude mountain forests and open fields at over in altitude.Hermes, Marcel Gustavo and Kohler, Andreas. The genus Agelaia Lepeletier (Hymenoptera, Vespidae, Polistinae) in Rio Grande do Sul, Brazil. Rev. Bras. entomol.[online]. 2004, vol.48, n.1 [cited 2014-09-25], pp. 135-138Rodríguez-Jimenez, Andrea, & Sarmiento, Carlos E.. (2008). Altitudinal distribution and body resource allocation in a High Mountain social wasp (Hymenoptera: Vespidae). Neotropical Entomology, 37(1), 1-7. The wasp favors regions of more temperate climate as their preferred regions showed a range of temperatures from 4 °C-12 °C. A. pallipes builds nests in these forests and open fields; however, it is observed to be a ground nesting species with frequent colony displacement.Fowler, H.G. 1992. Social Facilitation During Foraging in Agelain (Hymenoptera: Vespidae). Naturwissenschaften. 79, 424. These wasps will not construct envelopes for their nests and, instead, will prefer to obscure themselves in the cavities of tree trunks.Hermes, Marcel Gustavo and Kohler, Andreas. The genus Agelaia Lepeletier (Hymenoptera, Vespidae, Polistinae) in Rio Grande do Sul, Brazil. Rev. Bras. entomol.[online]. 2004, vol.48, n.1 [cited 2014-09-25], pp. 135-138 In addition to tree trunks, A. pallipes will construct their nests in armadillo tunnels, hollow logs, and man-made constructions. In temperate climates, A. pallipes is found to be among the most abundant species along with its close relative, A. vicina.Thiago de Carvalho Moretti et al., 2011. Bait and Habitat Preferences, and Temporal Variability of Social Wasps (Hymenoptera: Vespidae) Attracted to Vertebrate Carrion. Journal of Medical Entomology. 48(5): 1069-1075.
Colony cycle
An important characteristic of A. pallipes is its swarm-founding behavior. In swarm-founding species, a large group of workers and one or more queens initiate a new colony and subsequently display polygynic behavior. In contrast to independent-founding species that engage in continuous construction of nests, swarm-founding A. pallipes will engage in periodic construction where the nest is rapidly built to sustain a specific population size. After which, the nest size stays static until capacity is reached and subsequent expansion is necessary where thousands of cells can be built within days.De Oliveira, Otavio, et al. 2010. Foraging Behavior and Colony Cycle of Agelaia vicina (Hymenoptera: Vespidae; Epiponini). Journal of Hymenoptera research.
The colony cycle is the developmental period between one reproductive episode and the next. For swarm-founding species like A. pallipes, new colony reproduction is not necessarily coupled with queen production.Hastings, M.D., Strassmann J.E. 1998. Kin selection, relatedness, and worker control of reproduction in a large-colony epiponine wasp, Brachygastra mellifica. Behavioral Ecology. 9(6): 573-581. Due to their region of preference, the neotropics, the onset of nest foundation varies over a number of months and even seasons exclusive of only the deepest of winter periods. Therefore, unlike its relatives in temperate regions, nest foundation is not limited to the beginning of the favorable season.F. B. Noll & R. Zucchi (2000) Increasing caste differences related to life cycle progression in some neotropical swarm-founding polygynic polistine wasps (Hymenoptera Vespidae Epiponini), Ethology Ecology & Evolution, 12:1, 43-65
Behavior
As seen in the dimorphism between queens and workers, castes can be determined based on both behavior and morphology. As part of the Epiponini tribe, A. pallipes is characterized by being neotropical, polygynous and in relative abundance. The queens’ primary job is to reproduce whereas the workers are charged with foraging for food, caring for the larvae and defending the nest.Noll, F.B., Zucchi R. 2002. Castes and the influence of the colony cycle in swarm-founding polistine wasps. Insectes Sociaux. 49: 62-74. As necessary with this type of hierarchy, there must be a mechanism for distinguishing between females’ ability to reproduce in a social setting. This reproductive control or suppression has been recently credited to pre-imaginal caste determination via the mechanism of insemination.O’Donnell, S. 1998. Reproductive Caste Determination in Eusocial Wasps (Hymenoptera: Vespidae). Annual Review of Entomology. 43: 323-46. The lack of intermediate females (workers with developed ovaries) implies heavy control of reproduction.Biao, M., et al. 2003. Shape differences rather than size differences between castes in the Neotropical swarm –founding wasp Metapolybia docilis (Hymenoptera: Veispidae, Epiponini). BMC Behavioral Ecology. It is hypothesized that only with the advent of insemination, the female will then be able to develop their ovaries adequately to become a layer.Noll, F.B., Zucchi R. 2002. Castes and the influence of the colony cycle in swarm-founding polistine wasps. Insectes Sociaux. 49: 62-74. Observation has denoted that interactions among queen A. pallipes are unaggressive therefore implying that workers are most important in queen selection.Noll, F.B., Zucchi R. 2002. Castes and the influence of the colony cycle in swarm-founding polistine wasps. Insectes Sociaux. 49: 62-74.
As a swarm-founding species, it has been observed that in order to communicate at a macro level, individuals will leave a leave a pheromone trail for other members of the nest to follow. Rubbing their gastral sternites on objects when moving in the swarm leaves this trail.Smith, A., O’Donnell, S. 2002. Evolution of Swarm Communication in Eusocial Wasps (Hymenoptera: Vespidae). Journal of Insect Behavior. 15(6)
Polyethism
There is clear polyethism among A. pallipes where the young workers care for the larvae and older workers forage and defend the nest.Torres, V., et al., Temporal polyethism and life expectancy of workers in the Eusocial wasp Polistes Canadensis Canadensis Linnaeus (Hymenoptera: Vespidae). Sociobiology 60(1):107-113. It is hypothesized that the young workers are delegated to stay in the nest and care for larvae because it is significantly safer within the confines of the nest while the older workers are outside being exposed to predation in order to increase life expectancy of the workers. Other activities performed by the older workers include removing larvae from the nest, rubbing gaster on the nest and destroying cells. Intra-cell activities like checking cells, moving gaster and self-grooming were all-indicative of younger workers.Torres, V., et al., Temporal polyethism and life expectancy of workers in the Eusocial wasp Polistes Canadensis Canadensis Linnaeus (Hymenoptera: Vespidae). Sociobiology 60(1):107-113. Therefore, there is a clear relation between age and function thus implying that A. pallipes displays temporal polyethism behavior.
Morphology
There is clear dimorphism between queen and worker A. pallipes with the former caste observed to be physically superior in 22 characters.Noll, F.B., D. Simões & R. Zucchi. 1997. Morphological caste differences in Neotropical swarm-founding Polistinae wasps. Agelaia m. multipicta and A. p. pallipes (Hymenoptera: Vespidae). Ethol. Ecol. Evol. 9: 361-372. Pre-imaginal determination has been referenced to be the reason for differentiation between them. A stark difference between the two castes of females can be seen through examining their ovaries – type A ovaries display filament-appearance with no developed oocytes whereas type B ovaries were longer and well developed and coupled with several mature oocytes.Biao, M., et al. 2003. Shape differences rather than size differences between castes in the Neotropical swarm –founding wasp Metapolybia docilis (Hymenoptera: Veispidae, Epiponini). BMC Behavioral Ecology. Type B ovaries also contained sperm and could very clearly be categorized as those of queens where as type A ovaries were observed as uninseminated thus identifying as those of workers. This dimorphism displays strong control of sexual organs upon pre-imaginal determination.