Ecological and Forensic Implications of Social Wasps on Pig Carcass Degradation in Brazilian Savannah

Abstract

Abstract.Herein are recorded the composition and richness of 188 specimens of social wasps collected processing pig carcasses (Sus scrofa L.) in a Brazilian Savannah. Among the species collected Polybia (Myrapetra) fastidiosuscula de Saussure, 1854 (n = 178), Polybia (Trichotorax) ignobilis (Haliday, 1836) (n = 6), Apoica (Apoica) gelida Van der Vecth, 1972 (n = 3) and Polybia (Trichotorax) sericea (Olivier, 1791) (n = 1) were founded using fresh, bloated, decayed and skeletonized pig caracass. P. fastidiosuscula showed significant differences among decomposition stages, with preference for the bloated stage. The high abundance of social wasps in animal carcasses under decomposition, mainly those considered necrophagous, reveals the ecological importance of these wasps in carcass fragmentation by directly influencing the duration of the decomposition process. Moreover, the preference of P. fastidiosuscula for the bloated stage may be used as subsidy for forensic implications.

Ecosystem services provided by aculeate wasps

“…Previous evidence suggests necrophagy by polistine wasps in Central and South America, with the swarm‐founding genera Polybia , Agelaia , Angiopolybia , Brachygastra , Parachartergus , Protonectarina and Synoeca feeding on a wide range of wild ‘carrion’ from large insects to birds, reptiles, and mammals, to agricultural waste such as poultry, pigs and rats, and tuna fish baits laid out for ants (O'Donnell, 1995; Gomes et al ., 2007; Somavilla, Linard & Rafael, 2019). More recently, Apoica and Polybia have been reported scavenging on fresh and decaying pig carcasses under natural conditions in Brazil (Simões et al ., 2013); six species of Epiponines in Brazilian rainforest were detected using carrion traps (Silveira et al ., 2005) and 10 species were collected from carcasses of rats in similar environments (Somavilla et al ., 2019), with different species compositions on fresh and decaying cadavers; interestingly, wasps visiting the heavily decomposed cadavers were also observed preying on the fly eggs and larvae of Sarcophagidae and Calliphoridae (typically the first flies to colonise such carcasses) that were present. Finally, Vespula species are reported to scavenge on honey bee corpses (Pusceddu et al ., 2018).…”

“…Different species of wasps have been reported at the same carcasses in the early and late stages of decay, raising the possibility that the type of wasp species could indicate, albeit qualitatively, the time since death. Unfortunately, wasp necrophagy may also add confusion to forensic investigations: the insects tend to remove lumps of tissue from cavities such as noses, mouth, ears and anus, altering the skin texture, size of cavities, and apparent injuries that may confuse post‐mortem results, leading to errors in forensic investigations regarding the cause or mode of death (Moretti et al ., 2008; Simões et al ., 2013; Somavilla et al ., 2019).…”