The fate of small-mammal carrion is affected by carcass size and visual conspicuousness in a Neotropical rainforest

Abstract

Scavenging of carrion is essential to terrestrial ecosystems and can shape food webs and behavior. The prevalence and importance of scavenging has often been underestimated and overlooked in food web studies. Small-mammal carrion is even less studied and difficult to estimate, especially in the Neotropics. This project explored small-mammal carcass scavenging in a Neotropical, mid-elevation rainforest, and specifically studied the rate of carcass removal by scavengers, how the conspicuousness and weight of carcasses affect scavenging, and what vertebrate scavengers utilize this carrion resource. I deployed 194 mouse carcasses of various weights, above and below the leaf litter, and surveyed them daily until disappearance. I paired each carcass with a trail camera to help identify vertebrate scavengers. A general linear model analysis showed that most mouse carcasses disappeared within 1 to 2 days. Carcasses above the leaf litter were removed quicker and larger mice generally lasted longer. Only 6.25 % of the carcasses were removed by vertebrates. Most carcasses were removed by something too small to trigger the trail cameras, likely scarab beetles. The results of this study show that small-mammal carcasses are a sought-after resource in Neotropical forests, and that invertebrates are able to quickly hoard and secure small carrion more efficiently than vertebrate scavengers. A better understanding of scavenging ecology in Neotropical forests will help in developing a broader framework of the trophic interactions within and across ecosystems. El consumo de carroña es esencial en los ecosistemas terrestres e influye en la estructura de redes tróficas, así como la conducta animal. A pesar de eso, este es un aspecto poco estudiado en los estudios de redes alimentarias. El papel que juega la carroña de mamíferos pequeños ha sido aún menos estudiada y muy difícil de estimar, especialmente en el Neotrópico. En este estudio investigamos la recolección de carroña por parte de pequeños mamíferos en un bosque lluvioso neotropical de elevación media. Estudiamos específicamente la tasa de recogida de cadáveres por parte de los carroñeros, así como lo conspicuo y el peso de la carroña y como esos factores afectan su recolección, y qué recolectores de vertebrados utilizan la carroña. Con tal fin se colocaron 194 carroñas de ratones de peso variado, tanto encima como debajo de la hojarasca, y se examinaron diariamente hasta su desaparición. Se colocó una cámara video apuntando a cada carroña para ayudar a identificar los carroñeros de los vertebrados. Un análisis general de tipo lineal mostró que la mayoría de la carroña de ratones desaparecieron entre 1 y 2 días. La carroña por encima de la hojarasca se consumió más rápido y la carroña de mayor tamaño generalmente duró más. Sólo el 6.25 % de la carroña fue removida por vertebrados. La mayoría de la carroña fue removida por agentes demasiado pequeños para activar las cámaras y sospechamos que esos agentes eran escarabajos. Los resultados de este estudio sugieren que la carroña de...

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Factors affecting searcher efficiency and scavenger removal of bat carcasses in Neotropical wind facilities

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