Polybia emaciata

Appearance

"Polybia emaciata" shares many morphological characteristics with "Polybia singularis", another neotropical wasp species. The main differentiating aspect of this species is not its physical appearance but its nesting structure, which is famous for its closed pear shape and single circular opening at the bottom.

Behavior

While "Polybia emaciata" are much less aggressive as a group than other species in their genus, they are natural predators and are capable of fighting. When faced with danger, they use signaling techniques like wing waving and leg raising to warn others of their capabilities.

Habitat

"Polybia emaciata" mainly occupies South America in tropical climates, where fruit and predation is abundant. They are found in many South American countries such as Colombia, Venezuela, Brazil, and Argentina. Nests are built mainly around pastures and fruit crops on the branches of plants and trees. This is because their nests are energetically costly and it is best for them to build them where there are plenty of resources. "Polybia emaciata" is a fairly common species and has been used abundantly in the study of eusocial wasps.

Reproduction

Nests are often pear shaped and made primarily out of mud. "Polybia emaciata" nest are well known for having only one circular opening in the nest through which all wasps enter and exit. This allows for a unique defensive behavior, which is discussed later on in the defense section.Sometimes, there are intermediates in "Polybia emaciata "which are workers that used to be queens. It is likely that at the foundation of new nests they lost dominance competitions and lost their ability to produce eggs. Since they lost the dominance competition and there is limited space for the queens they lose their ability to reproduce.There seems to be no evidence for reproductive dominance, especially since more than one queen may be able to reproduce. There is also no evidence to suggest that younger or older queens have an advantage when it comes to the number of eggs laid. To note, however, high levels of relatedness in the species would be more easily explained if dominance was present but that is not the case with "Polybia emaciata".

Food

"Polybia emaciata" eats of steady fluid diet which includes nectar, but also eats other insects. It eats many species of flies and beetles. Diptera, Coleoptera, Hemiptera, Lepidoptera, Hymenoptera, Neuroptera, Orthoptera, Araneae, and Isopoda are all part of its diet.

Predators

"Polybia emaciata" have several vertebrate predators, and in some cases they are victim to nest parasite predation. Birds, bats, primates and army ants are among the most prevalent.

Defense

"Polybia emaciata" have a unique form of defense that stems from the very way they build their nest. Because their nest is made of mud which is much stronger than the leaf nests of other wasps in its species it is much more durable. In fact the build quality of the nests allows for the first line of defense used by "Polybia emaciata" to be doing nothing. They will not leave the nest and attack unless the nest is bothered for a long period of time. Other wasps in their genus will attack almost as soon as their nests are threatened but "Polybia emaciata" are much less willing to attack.