Exoskeletal Thinning in Cephalotes Atratus Ants (Hymenoptera: Formicidae) Parasitized by Myrmeconema Neotropicum (Nematoda: Tetradonematidae)

Abstract

Some parasites modify the color of their arthropod hosts, presumably to facilitate transmission to a new host. Mechanisms for such changes often are unknown, but altered exoskeletal color in adult insects typically occurs via structural modifications or redistribution of pigments. Here, we examine the cuticle structure of workers of the Neotropical canopy ant Cephalotes atratus infected with the nematode Myrmeconema neotropicum. We hypothesized that the conspicuous red color of the gaster (the globular posterior body region) of infected ants results from structural changes, specifically localized exoskeletal thinning. We used scanning electron microscopy to quantify the thickness of gaster cuticle in healthy and infected ants. For comparison, we also measured the cuticle thickness of the head of each ant, which is black in both infected and healthy individuals. The gaster cuticle was 23% thinner in infected ants (average ±SE: 14.8 ± 1.02 µm) versus healthy ants (19.2 ± 0.65 µm) after correcting for body size. In contrast, the thickness of the head exoskeleton was similar among groups. We conclude that parasite-induced thinning of the exoskeleton is associated with the red color of the gaster. Other mechanisms, including translocation or leaching of melanin (by the ant or the parasite, respectively) may operate in concert with thinning to effect the color change, and would be an appropriate extension of this research.

Department(s)

Biological Sciences

Keywords and Phrases

Melanin, Ant; Body Size; Color; Developmental Biology; Host-Parasite Interaction; Melanin; Nematode; Parasitism; Scanning Electron Microscopy; Translocation, Ant; Article; Body Size; Cephalotes Atratus; Comparative Study; Exoskeleton; Head; Myrmeconema Neotropicum; Nematode; Nonhuman; Scanning Electron Microscopy, Animals; Ants; Host-Parasite Interactions; Microscopy, Electron, Scanning; Nematoda; Pigmentation, Arthropoda; Cephalotes Atratus; Formicidae; Hexapoda; Hymenoptera; Nematoda; Tetradonematidae

International Standard Serial Number (ISSN)

0022-3395

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2012 American Society of Parasitologists, All rights reserved.

Publication Date

01 Feb 2012

PubMed ID

21834724

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