Bat Colony and Cave Zone Shape Arthropod Assemblages in Levantine Caves

Area of Science:

• Cave ecology and biodiversity.
• Subterranean ecosystem functioning.
• Arthropod community dynamics.

Background:

• Caves possess unique abiotic conditions, including limited light, fostering distinct, often endemic, faunal assemblages.
• Subterranean food webs lack photoautotrophs, relying heavily on allochthonous nutrient inputs, leading to lower diversity than epigean ecosystems.
• Bat guano, a key nutrient source, varies in composition based on bat diet (frugivorous vs. insectivorous) and deposition site.

Purpose of the Study:

• To investigate the influence of allochthonous nutrient sources and cave zones on arthropod diversity and assemblage composition.
• To determine how bat guano origin and cave microhabitats affect subterranean arthropod communities.
• To understand the ecological drivers of diversity in hypogean habitats.

Main Methods:

• Comparative analysis of arthropod assemblages across caves with varying bat colony types (frugivorous, insectivorous, none).
• Assessment of nutrient source impact (bat guano composition and location) on arthropod communities.
• Examination of species diversity and assemblage differences between cave twilight and dark zones.

Main Results:

• Arthropod assemblage composition is strongly influenced by nutrient source type and cave characteristics.
• Caves with frugivorous bats showed lower fly abundance compared to caves with insectivorous bats or no bats.
• Caves without bats had lower detritivore and predator species richness than caves with bats; species diversity varied significantly between twilight and dark zones.

Conclusions:

• Allochthonous nutrient sources, ecological zones, and microhabitats are critical drivers of cave arthropod diversity and composition.
• Bat presence and diet significantly impact cave arthropod community structure.
• Conserving diverse cave types is essential for protecting unique subterranean arthropod biodiversity.