Insect abundance patterns on vertebrate remains reveal carrion resource quality variation

Abstract

Resource quality is a key driver of species abundance and community structure. Carrion is unique among resources due to its high nutritional quality, rapidly changing nature, and the diverse community of organisms it supports. Yet the role resource quality plays in driving variation in abundance patterns of carrion-associated species remains poorly studied. Here we investigate how species abundances change with a measure of resource change, and interpret these findings to determine how species differ in their association with carrion that changes in quality over time. We conducted field succession experiments using pigs and humans over two winters and one summer. We quantified the effect of total body score, an objective measure of resource change, on adult insect abundance using generalised additive models. For each species, phases of increasing abundance likely indicated attraction to a high-quality resource, and length of abundance maxima indicated optimal oviposition and feeding time. Some species such as the beetle Necrobia rufipes had a rapid spike in abundance, suggesting a narrow window of opportunity for carrion resource exploitation, while species like the wasp Nasonia vitripennis had a gradual change in abundance, indicating a wide window of resource exploitation. Different abundance patterns were also observed between species occurring on pigs and humans, suggesting cadaver type is an important aspect of resource quality. Our findings show that species abundances, unlike species occurrences, can reveal additional detail about species exploitation of carrion and provide information about how resource quality may drive competition and variation in insect community succession.

Aggregation in an heterospecific population of blowfly larvae: social behaviour is impacted by species-specific thermal requirements and settlement order

“…From an evolutionary point of view, it means that individuals of both species must have a shared interest and benefits in cooperation. This is often the case on transient resources that are being rapidly depleted, as observed on carcasses [6,14,[57][58][59].…”

The ephemeral resource patch concept

“…For example, in the presence of species A, the fitness of species B (a competitor) will be reduced, while the fitness of species C (a mutualist) will be enhanced. Thus, increased species richness and abundance, and subsequent priority effects, can be beneficial for some species through facilitation (Komo et al ., 2019), while being detrimental for other species through increased competition or predation (Brundage, Benbow & Tomberlin, 2014; Dawson et al ., 2022 a ). Generalist consumers, such as the Australian carrion muscid Australophyra rostrata (Dawson, Barton & Wallman, 2020; Dawson et al ., 2022 b ), may be able to tolerate a broad range of species compositions, whereas specialist consumers often depend on the presence/absence of certain species (i.e.…”

“…Generalist consumers, such as the Australian carrion muscid Australophyra rostrata (Dawson, Barton & Wallman, 2020; Dawson et al ., 2022 b ), may be able to tolerate a broad range of species compositions, whereas specialist consumers often depend on the presence/absence of certain species (i.e. arrival before predators or competitors, or after mutualists) to enhance their chances of survival (Morais et al ., 1995; Brundage et al ., 2014; Dawson et al ., 2022 a ).…”

“…damselflies; Nilsson‐Örtman & Rowe, 2021) and lower developmental thresholds, enabling earlier maturation (Blanckenhorn, 1998; Nilsson‐Örtman & Rowe, 2021). There are also surprising examples of trophic plasticity dependent upon resource availability – with trophic shifts that occur when resources are limited – from mycophagy to predation in nematodes (Kanzaki, Ekino & Giblin‐Davis, 2019), and from saprophagy to predation in carrion‐breeding blowflies (Dawson et al ., 2022 a ). All these strategies can be of substantial adaptive benefit when utilising highly variable and unpredictable resources such as ERPs, however, many key questions remain unanswered.…”

Not all dung beetles feed on dung: Scarabaeinae (Coleoptera: Scarabaeidae) attracted to different carrion types in contrasting habitats at Brazilian Amazon

“…Decomposing carcasses are nutritiously rich in microorganisms and bear a doughy texture which favours its use by a wide array of animals (Dawson et al, 2022; Favila, 1993; Selva et al, 2005). Species that feed on carrion occupy an ecologically interesting niche, due to limited spatio‐temporal availability of carrion, even when compared to other decaying resources (Barton et al, 2013; Halffter & Matthews, 1966; Turner et al, 2017).…”