Wasps of the cosmopolitan genus Polistes are the most familiar of the polistine
wasps, and are the most common type of paper wasp in North America. It is also
the single largest genus within the family Vespidae, with over 300
recognized species and subspecies. Their innate preferences for nest-building
sites leads them to commonly build nests on human habitation, where they can be
very unwelcome; although generally not aggressive, they can be provoked into
defending their nests. All species are predatory, and they may consume large
numbers of caterpillars, in which respect they are generally considered
beneficial. The European paper wasp, Polistes dominula, was introduced into
the US about 1981 and has quickly spread throughout most of the country, in most
cases replacing native species within a few years. This species is very commonly
mistaken for a yellowjacket, as it is black, strongly marked with yellow, and
quite different from the native North American species of Polistes. The cuckoo
wasp, Polistes sulcifer, is an obligate social parasite, whose only host is P.
dominula. Polistes annularis, whose species name is Latin for "ringed", is
also known for its distinctive red body color. Polistes metricus adults malaxate
their insect prey by chewing them into a pulp, sucking out and ingesting the body
fluids, then feed the rest of the morsel to their larvae. The most widely
distributed South American wasp species, Polistes versicolor, is particularly
common in the southeastern Brazilian states. This social wasp is commonly
referred to as the yellow paper wasp due to the distinct yellow bands found on
its thorax and abdomen. Polistes wasps can be identified by their
characteristic flight; their long legs dangle below their bodies, which are
also more slender than a yellowjacket. Lifecycle
The general lifecycle of Polistes can be divided into four phases:
Founding phase Worker phase
Reproductive phase Intermediate phase
= Founding phase = The founding stage begins in the spring
when a solitary female initiates the construction of a nest. The wasps begin
by fashioning a petiole, a short stalk which will connect the new nest to a
substrate, and building a single brood cell at the end of it. Further cells are
added laterally in a hexagonal pattern, each cell surrounded by six others.
Although nests can achieve impressive sizes, they almost always maintain a
basic shape: petiolated, single-combed, unprotected, and open.
Eggs are laid by the foundress directly into the brood cells and are guarded by
the foundress and the assisting females. After the first larvae hatch, the
foundress feeds them via progressive provisioning, bringing softened
caterpillar flesh to the larvae multiple times throughout their development. Each
of this first seasonal brood of new paper wasps is exclusively female and
destined to a subordinate worker position inside the nest; they do not
found their own nests and instead assist their mother in the care and maintenance
of future sisters. Some foundress wasps do not build their
own nests, but rather attempt to usurp that of another female. These usurpation
attempts may or may not be successful, but almost always result in impressive
displays of aggression and violence. Females may also adopt a more peaceful
alternative reproduction strategy by joining the nest of a close relative and
working as assisting females. In the latter case, such cofounding females are
generally, but not exclusively, close relatives.
= Worker phase = The worker phase usually begins in the
early summer, roughly two months after colony initiation, with the emergence of
the first workers. These new females take up most of the colony's work
duties, foraging, caring for brood, and maintaining the structure of the nest.
Around this time, those females which assisted in nest foundation are driven
from the nest by aggressive behavior on the part of the foundress, and leave
either to start their own late-season nests or usurp another's.
= Reproductive phase = The reproductive phase of the colony
begins when the first female reproductives emerge from their brood
cells. These reproductives differ from their worker sisters by having increased
levels of fat stores and cryoprotectant carbohydrate compounds. These
reproductives contribute genes directly to the next generation, while their
worker sisters normally pass along their genes indirectly.
= Intermediate phase = Once male reproductives emerge and both
males and females disperse from the natal nest for mating flights, the
so-called intermediate phase begins. Brood care and foraging behavior decline
and worker numbers drop as dying individuals are no longer replaced by
new ones. Intracolonial aggression increases and the social cohesion of the
nest declines. In temperate Polistes species, individuals gather in groups of
up to 50 individuals and seek a sheltered location in which to
overwinter. Behavior
= Kin selection = The reproductive behavior of Polistes
wasps provided some of the first evidence for the mathematical biologist
W. D. Hamilton's 1964 theory of kin selection. Hamilton showed that animals
such as workers could be expected to provide assistance to relatives such as
their queens according to the costs and benefits involved and their degree of
genetic relatedness, and gave the rule that now carries his name, K > 1/r.
Early caution existed among researchers as to whether social insects could
really assess their relatedness. Hamilton himself suggested an
alternative possibility, namely that kin could become associated simply by
"population viscosity"—that offspring tend not to disperse far from their
birthplaces—and West-Eberhard found some evidence for this in Polistes. However,
Polistes species are now known to learn and remember chemical signals picked up
from the nest to distinguish nestmates accurately from nonrelatives.
= Dominance hierarchy system = Morphologically, the foundress and
subordinate reproductive members of the colony differ little. However,
behavioral differentiation occurs among females both between and within
generations. For example, in the species Polistes humilis the queen displays a
"tail-wagging" behavior to assert her dominance over the worker class.
Similarly, Polistes canadensis also possesses behavioral differentiation
between the queen and her nestmates, with the queen often suppressing the
aggressive behavior of subordinates through lateral abdominal vibrations and
stroking. In contrast, unmated females are not aggressive. In Polistes
exclamans queens have different amounts of glucose, fructose, and trehalose
which lead to different cryoprotectant levels. This alters their survivability
in different temperatures, increasing their odds of reproduction. Females in
P. bellicosus are also morphologically similar between caste separations. For
example, a P. bellicosus worker could become queen, and egg-layer, if all of
the original foundresses die or leave the nest. This is also true for Polistes
dorsalis, which also displays dominant behavior. Despite having no distinct
morphological caste, roles of P. dorsalis tend to be fixed in a system
with division of labor. = Nestmate recognition =
Polistes spp. discriminate colony mates using an acquired cue, absorbing
hydrocarbons from the natal nest at eclosion. This cuticular hydrocarbon
"signature" is derived both from the plant material and the foundress-applied
substances from which the nest is made. Studies of Polistes fuscatus have
researched the molecular basis of the recognition "pheromone" used by the
wasps, and indicate at least some of the recognizable labels have the same
chemical constituents as the adult cuticular hydrocarbons. Similar
recognition is found in Polistes metricus.
Dominant individuals of P. dominula have differing cuticular profiles from
workers, and the frequent observations of the dominant female stroking its
gaster across the nest surface, combined with its staying on the nest for longer
times than subordinates, suggests the dominant individual may contribute more
to the nest odor. P. carolina females do not
preferentially feed their own progeny, so it may be the case that nest odor
only serves as a likely indicator of relatedness, rather than a specific
label of kinship. Further to this recognition of
nestmates, Polistes biglumisfoundresses discriminate between 'alien' eggs and
their own via differential oophagy. The mechanism of differentiation is not
elucidated, but is thought to be based upon differences in cuticular
hydrocarbon odor. Gallery
Species Pest status
Along with the German and common wasps, the Asian and Australian paper wasps are
considered pests in New Zealand. Arriving in 1979, the Asian paper wasp
has established itself on both the North Island and the northern parts of the
South Island. Because it competes with native species for insects, nectar, and
honeydew, it is a hindrance to conservation efforts.
Parasites Various other insects are parasites or
parasitoids of Polistes, including flies, mantispids, and wasps in the
families Torymidae, Mutillidae, Braconidae, and Ichneumonidae. Some more
specialized groups are more intimately associated with Polistes; this includes
strepsipterans in the family Stylopidae, wasps of the genus Elasmus, and wasps in
the family Trigonalidae. Within the Polistes family are three
known social obligate parasites: P. sulcifer, P. atrimandibularis, and P.
semenowi, which parasitize other Polistes wasps. Known host species of
these parasites are P. dominulus, P. gallicus, P. nimphus, P. associus, and
P. biglumis. Although these parasites differ in their host invasion
strategies, their end goal is to successfully infiltrate the host nest
and reproduce at the host's expense. References
Further reading Stefano Turillazzi & Mary Jane
West-Eberhard. The Natural History and Evolution of Paper-Wasps. Oxford
University Press. ISBN 978-0-19-854947-5.
I. Karsai & G. Theraulaz. "Nest building in a social wasp: postures and
constraints". Sociobiology 26: 83–114. I. Karsai & Z. Penzes. "Intra-specific
variation in the comb structure of Polistes dominulus: parameters,
maturation, nest size and cell arrangement". Insectes Sociaux 43:
277–296. doi:10.1007/BF01242929. External links
Paper wasp Polistes dominula reference photographs, descriptions, taxonomy
Paper wasp Polistes fuscatus diagnostic photographs, natural history
Polistes dominula facial markings indicating dominance
Red wasps from www.whyistheanswer.com