Population Structure of the Ant Nest Symbiont Masoncus pogonophilus (Araneae: Linyphiidae)

Abstract

Myrmecophiles are arthropods that spend all or part of their life cycles living inside ant nests. However, little is known about how the distribution of host colonies in a habitat affects the dispersal and population structure of these symbionts. The polymerase chain reaction-based random amplified polymorphic DNA technique (RAPD-PCR) was used to investigate the population structure of the myrmecophilic spider, Masoncus pogonophilus Cushing (Linyphiidae), by examining the genetic diversity of 2 spider populations living in the nest chambers of adjacent ant colonies and a 3rd living in a distant colony. Using the analysis of molecular variance technique, I found that, of the total genetic diversity, 77.4% was attributable to intrapopulation differences, 18.2% to differences between the distant populations, and only 4.4% to differences between the neighboring populations. The Lynch and Milligan technique also indicated that neighboring populations differed from distant populations in their mean genetic diversity: the mean genetic diversity between neighboring populations was 0.7%, whereas the mean genetic diversity between distant pairs of populations was 1.8 to 3.5%. Both analyses suggest that spiders from neighboring nests are more similar in their genetic makeup than spiders from distant nests. Dispersal events of spiders between neighboring colonies may maintain this genetic similarity between neighboring populations.