Delayed insect access alters carrion decomposition and necrophagous insect community assembly

Abstract

Abstract. Vertebrate carrion in terrestrial ecosystems is an unpredictable, ephemeral resource pulse that contributes to local biodiversity and nutrient transformation dynamics. Carrion ecology is infrequently studied compared to other decomposition systems, such as leaf litter detritus, despite its importance as a resource subsidy in most ecosystems. We hypothesized that delayed insect access to carrion (insects excluded for five days) would demonstrate marked shifts in necrophagous insect community structure, turnover rates and assembly with overall effects on carrion decomposition. Despite similarities between taxon arrival patterns, once insects were allowed to colonize carrion previously excluded from insects there was an increased necrophagous insect taxon richness and increased community turnover rates. Additionally, during the first five days of decomposition, insect exclusion carcasses remained in bloat stage while those naturally colonized were well advanced in active decomposition. This resulted in substantial differences in decomposition and highlighted the importance of insect community assembly in the decomposition process. Carrion decomposition has been a neglected field of study compared to other organic matter processes (e.g., leaf detritus), and these data suggest the ecology of carrion-arthropod interactions can contribute to a broader understanding of decomposition processes and ecosystem function.

Using bacterial and necrophagous insect dynamics for post-mortem interval estimation during cold season: Novel case study in Romania

“…However, the temperature throughout the course of this study played a major role in the rate of decomposition, mainly due to its influence on the decomposers community (insects and microorganisms). For instance, the appearance of necrophagous insects is influenced primarily by temperature and the ability to reach the corpse [43,62]. The higher temperatures recorded during the first week permitted carcasses visits by two species of Calliphoridae, only one of which (C. vicina) oviposited.…”

“…In particular, chronological and spatial variation of microbial communities could provide data to complement entomological evidence or perhaps, with additional research, serve as physical evidence in cases where necrophagous insects are less active in low temperature conditions (during night time and/or winter season), and in unforeseen circumstances that prevent the cadaver colonization such as freezing, depth of burial or plastic bags [41][42][43]. So far, few studies have considered the possibility of using post-mortem microorganisms to estimate PMI [37][38][39], but the identification of microorganisms from the soils associated with corpses has begun [37,40].…”

Applying standardized decomposition stages when estimating the PMI of buried remains: reality or fiction?

“…Bonacci 42 verified complete skeletonization after nine days in the summer, while Castro 43 verified complete skeletonization after 15 days, also in summer. In a temperate climate, skeletonization was observed after six/seven days of exposure 44 , whilst according to Galloway et al 14 this state is more likely to occur six months after death. Thus, when comparing the given time-periods to those observed in this study, it is reasonable to state that there is a distinct decay progression when observing air-exposed versus buried remains.…”

“…Thus, it seems that, despite not presenting a statistical significance, a longer burial leads to an accelerated degradation, as opposed to storage, where even longer time periods do not seem to heavily influence bone breakdown. Many authors underline the influence of soil on bone decay due to chemical reactions, bacteria, fungi, plant roots and others 5,44,47 , turning this environment, after the coffin's breakdown, more hostile for bone preservation than indoor scenarios such as storage. We can affirm that different deposition environments, in this case burial and storage, have a different effect on bone degradation.…”

Keratin subsidies promote feather decomposition via an increase in keratin-consuming arthropods and microorganisms in bird breeding colonies

“…Consequently, large amounts of keratin likely accumulate in bird colonies (Sugiura and Ikeda 2014). Although the decomposition process of vertebrate carcasses has been frequently investigated (Carter et al 2007;Parmenter and MacMahon 2009;Mondor et al 2012;Pechal et al 2014), very few studies have focused on the decomposition of keratin materials such as feathers under field conditions (Sugiura and Ikeda 2014). Keratin is one of the most abundant and highly stable animal proteins on earth (Sharma and Rajak 2003).…”