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Washington University in St. Louis

Publication Date

Fall 2022

Program Name

Ecuador: Comparative Ecology and Conservation

Abstract

As abundant predators at the top of arthropod food chains, spiders are excellent bioindicators. Araneae is a megadiverse and extremely understudied order, especially in the tropics. This study aims to investigate the diversity of orb-weaver spiders across a disturbance gradient and variety of habitat types as well as their microhabitat preferences and potential niche partitioning. Spider collection was performed on spiders of the families Araneidae, Tetragnathidae, and Theridiosomatidae in Sumak Kawsay in Situ biological reserve in the lower elevation cloud forest of Ecuador’s Andean foothills. Spiders and webs were observed and analyzed from primary and secondary forest tree fall gaps, stream corridors in primary and secondary forests, and open areas in cultivated land around the lodge. In general, orb-weaver diversity decreased from primary to secondary to cultivated habitat and there was very little species overlap between forested sites and cultivated sites. The family distributions varied between the habitat types: tree gaps, streams, and cultivated open areas. No dependence was found between various ecological variables within the samples. However, the relative abundance of different morphospecies across height strata demonstrated separate niches were occupied by different species. Additionally, the height strata where webs were found varied with the microhabitat and vegetative qualities present in the different habitat types. With an increase in microhabitat complexity, there was an increase in available niches and thus in orb-weaver diversity.

Disciplines

Biodiversity | Environmental Indicators and Impact Assessment | Latin American Studies | Research Methods in Life Sciences | Terrestrial and Aquatic Ecology | Zoology

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