Title

Assessing effects of non-native crayfish on mosquito survival

Document Type

Article

Publication Date

2-1-2019

Keywords

cangrejo de río, crayfish, enfermedades transmitidas por vectores, especie invasora, invasive species, Montañas de Santa Mónica, odonates, odonatos, Procambarus, Procambarus, Santa Monica Mountains, vector-borne diseases

Abstract

Introductions of non-native predators often reduce biodiversity and affect natural predator–prey relationships and may increase the abundance of potential disease vectors (e.g., mosquitoes) indirectly through competition or predation cascades. The Santa Monica Mountains (California, U.S.A.), situated in a global biodiversity hotspot, is an area of conservation concern due to climate change, urbanization, and the introduction of non-native species. We examined the effect of non-native crayfish (Procambarus clarkii) on an existing native predator, dragonfly nymphs (Aeshna sp.), and their mosquito larvae (Anopheles sp.) prey. We used laboratory experiments to compare the predation efficiency of both predators, separately and together, and field data on counts of dragonfly nymphs and mosquito larvae sampled from 13 local streams. We predicted a lower predation efficiency of crayfish compared with native dragonfly nymphs and a reduced predation efficiency of dragonfly nymphs in the presence of crayfish. Dragonfly nymphs were an order of magnitude more efficient predators than crayfish, and dragonfly nymph predation efficiency was reduced in the presence of crayfish. Field count data showed that populations of dragonfly nymphs and mosquito larvae were strongly correlated with crayfish presence in streams, such that sites with crayfish tended to have fewer dragonfly nymphs and more mosquito larvae. Under natural conditions, it is likely that crayfish reduce the abundance of dragonfly nymphs and their predation efficiency and thereby, directly and indirectly, lead to higher mosquito populations and a loss of ecosystem services related to disease vector control.

Publication Title

Conservation Biology

ISSN

08888892

E-ISSN

15231739

Volume

33

Issue

1

First Page

122

Last Page

131

DOI

10.1111/cobi.13198

PubMed ID

30079610

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