''Agelaia pallipes'' is a species of
social
Social organisms, including human(s), live collectively in interacting populations. This interaction is considered social whether they are aware of it or not, and whether the exchange is voluntary or not.
Etymology
The word "social" derives fro ...
paper wasp
Paper wasps are a type of Eusociality, social vespid wasps. The term is typically used to refer to members of the Vespidae, vespid subfamily Polistinae, though it often colloquially includes members of the subfamilies Vespinae (hornets and yel ...
found from
Costa Rica
Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...
to
Brazil
Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
,
Argentina
Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...
and
Paraguay
Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...
. ''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
The Vespidae are a large (nearly 5000 species), diverse, cosmopolitan family of wasps, including nearly all the known eusocial wasps (such as '' Polistes fuscatus'', '' Vespa orientalis'', and ''Vespula germanica'') and many solitary wasps. Eac ...
, subfamily
Polistinae
The Polistinae is a subfamily of eusocial wasps belonging to the family Vespidae. They are closely related to the wasps (“yellowjackets” as they are called in North America) and true hornets of the subfamily Vespinae, containing four tribes ...
, tribe
Epiponini
The Epiponini (formerly known as Polybiini) are a large and diverse tribe of social wasps inhabiting the Neotropical region, with some species' ranges extending into the Nearctic
The Nearctic realm is one of the eight biogeographic realms ...
, and subsequently the genus ''
Agelaia''. Vespidae is characterized by the
eusociality
Eusociality ( Greek 'good' and social) is the highest level of organization of sociality. It is defined by the following characteristics: cooperative brood care (including care of offspring from other individuals), overlapping generations wit ...
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. 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.
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
A ''tergum'' (Latin for "the back"; : ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod segment other than the head. The anterior edge is called the 'base' and posterior edge is called the 'apex' or 'margin'. ...
vary from yellow to brown and black. Their legs and wings are also yellow. 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
The mesosoma is the middle part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the metasoma. It bears the legs, and, in the case of winged insects, the wings.
Wasps, bees and a ...
,
metasoma
The metasoma is the posterior part of the body, or tagma (biology), tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the mesosoma. In insects, it contains most of the digestive tract, respiratory sy ...
and wings. There is also clear dimorphism between
ovary
The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are end ...
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. Found in ground cavities, their nests are found to have a maximum diameter of with a maximum of 16,500 individuals.
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. 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. These wasps will not construct envelopes for their nests and, instead, will prefer to obscure themselves in the cavities of tree trunks. 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''.
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.
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. 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.
Behavior
As seen in the dimorphism between queens and workers, castes can be determined based on both behavior and
morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
*Morphology (archaeology), study of the shapes or forms of artifacts
*Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...
. As part of the Epiponini tribe, ''A. pallipes'' is characterized by being neotropical,
polygynous
Polygyny () is a form of polygamy entailing the marriage of a man to several women. The term polygyny is from Neoclassical Greek πολυγυνία (); .
Incidence
Polygyny is more widespread in Africa than in any other continent. Some scholar ...
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. 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. The lack of intermediate females (workers with developed ovaries) implies heavy control of reproduction. 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. Observation has denoted that interactions among queen'' A. pallipes'' are unaggressive therefore implying that workers are most important in queen selection.
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
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
trail for other members of the nest to follow. Rubbing their gastral sternites on objects when moving in the swarm leaves this trail.
Polyethism
There is clear polyethism among ''A. pallipes'' where the young workers care for the larvae and older workers forage and defend the nest. 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. 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. 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. 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.
''A. pallipes'' morphology is also affected by the altitude with an inverse relationship between higher altitude and reduction in body size, especially hind femur length and head width. The cloud forest environment, where some of these ''A. pallipes'' are found, contribute negatively to foraging activity and force individuals to complete life cycles with a smaller body size. This study along the altitudinal gradient provides insight on ''A. pallipes'' capacity to adapt morphologically to more severe conditions.
Kin and mate selection
Pre-imaginal determination is the predominant theory as to why certain females become reproductively capable over others. There is a lack of queen-queen aggression that suggests that only workers are involved in the queen selection process. The mechanism for workers choosing their queens is still unclear – however, the pervading theory is related to body size and that the largest females are chosen due to higher survivability. Research has also suggested that the workers have a mechanism for identifying those females who are more
fecund and allowing them to identify, and discard, those with less favorable ovaries.
Naturally, in a polygynic society of swarm-founding individuals with so many queens, kin selection becomes a challenge. With so many queens, it is expected to have a lower relatedness between workers and the larvae for which they care. Though it is expected that workers will strive to reproduce those who are most like themselves in order to pass on their genes,
eusociality
Eusociality ( Greek 'good' and social) is the highest level of organization of sociality. It is defined by the following characteristics: cooperative brood care (including care of offspring from other individuals), overlapping generations wit ...
still persists.
Feeding and foraging
''Agelaia pallipes'' will normally feed on other insects (flies, moths, butterflies), however, it has been recently discovered that A. pallipes will also feed on carrion. Though the collection of bodily fluids is preferred, the wasp will also settle to take carrion morsels to their larvae; furthermore, it has been documented in recent studies that they will chew tissues of cavities in order to find liquids. ''A. pallipes'' was observed to feed on
carrion
Carrion (), also known as a carcass, is the decaying flesh of dead animals.
Overview
Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
primarily during the fresh stage (98% of occurrences) which can lead to significant forensic importance when determining the post-mortem interval.
''A. pallipes'' has been observed to display social facilitation for recruitment to food resources. This type of behavior is seen in other carrion eaters like crows and ravens where the pooling of independent search efforts is the most efficient way to locate food sources and subsequently defend them from other organisms. This behavior can very quickly develop into an Evolutionary Stable Strategy for the species.
Competition
''A. pallipes'' have been observed to directly compete with several species of ants when contending for food resources. The ''A. pallipes'' workers, when approaching an occupied food source, will fly low and flap their wings in order to free areas. The workers will recruit other members of their species from the nest as a form of social facilitation and thus display increased dominance at resources by displaying their competitive behavior. Therefore, like social facilitation for feeding and foraging, the ''A. pallipes'' will attempt to recruit its nest mates in order to gain advantages over competitors.
''A. pallipes'' will compete with other species of wasp and will, due to its aggressiveness, generally be successful as seen in their superior abundance on carcasses in the primary stages of decay. However, even though ''A. pallipes'' is usually victorious in its interactions, it has been observed that ''A. pallipes'' will often be out-competed by certain species of stingless bees.
Communication
By virtue of such large numbers, swarm-founding members must necessarily have a method of communication that will allow the entire nest to coordinate movements efficiently. In a swarm-founding species like ''A. pallipes'', the main conduit of communication is through the use of pheromones. Most individuals of the tribe Epiponini have a Richard's gland to release the pheromones, which is an exocrine gland located on the underside the abdomen. However, it is absent in ''Agelaia'' and instead, it is hypothesized that the van der Vecht's gland is the alternative source for the communicative pheromone. By rubbing their gastral on objects, they leave a pheromone trail for their worker counterparts to follow suit.
As noticed in ''A. pallipes'' foraging habits, the eusocial wasps also receive visual stimulus that communicates to the individual to join the larger group. It was observed through bait stations that those stations with wasp models were better dominated by wasps when ant competition was also present. Furthermore, scientists have proved that even without their olfactory senses, the mere presence of wasp models was enough for recruitment. Thus it is clear that though ''A. pallipes'' communicate through the release of trail pheromones, they can also be recruited through simple visual stimuli.
Human importance and current research
Social wasps use venom to defend the nest from intruders and predators and have, in many instances, caused severe deleterious effects in major organs in the human body and other organisms. Due to the aggressiveness of ''A. pallipes'' and the number of instances between humans and wasps, the characterization of its venom has become an important issue for scientists.
Recent studies have characterized two novel
peptides
Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Dalton (unit), Da or more are called proteins. Chains of fewer t ...
in the venom of the social wasp: Protonectin and Agelaia-MP. The first venom, Protonectin, is found to be the same venom from relative neotropical social wasp, ''Protonectarina sylveirae''. In cohesion, the two peptide toxins were tested for and displayed potent ability to negatively effect
hemolytic
Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo ...
activity, mass cell granulation, and
chemotaxis
Chemotaxis (from ''chemical substance, chemo-'' + ''taxis'') is the movement of an organism or entity in response to a chemical stimulus. Somatic cells, bacteria, and other single-cell organism, single-cell or multicellular organisms direct thei ...
in large vertebrates. The inhibition of these activities can result in
anaphylactic shock, renal failure and
myonecrosis
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...
in humans. Certainly, the characterization and identification of these novel ''A. pallipes'' toxins will allow scientists to elucidate the mechanism of envenoming which will lead to future pharmacological breakthroughs.
[Baptista-Saidemberg, Nicoli, et al. 2011. Profiling the peptidome of the venom from the social wasp ''Agelaia pallipes pallipes''. Journal of Proteomics. 74(10): 2123-2137]
References
External links
''Agelaia pallipes'' Classification''A. pallipes'' Distribution
{{Taxonbar, from=Q14423297
Vespidae
Insects described in 1852