Pygidial secretions ofPasimachus subsulcatus (Coleoptera: Carabidae) deter predation byEumeces inexpectatus (Squamata: Scincidae)

The carabid beetlePasimachus subsulcatus is an abundant ground-dwelling insect in west central Florida that exudes a powerful mucous membrane irritant when disturbed. This secretion can be sprayed over 10 cm from the abdominal tip. The southeastern five-lined skink,Eumeces inexpectatus, is an abundant insectivorous lizard sympatric withPasimachus. We assessed the availability ofPasimachus toEumeces and found it to be within the foraging microenvironment of the lizard. Analysis ofEumeces gut contents and field feeding trials indicate thatPasimachus are not ingested by the lizard, yet arthropods of comparable size and exoskeletal thickness are ingested. The movement response ofEumeces to isolatedPasimachus secretion constituents, conducted in a modified Y-maze laboratory experiment, was used to assess the repellent capabilities of the secretion.Eumeces are consistently repelled byPasimachus secretion constituents, indicating that the beetle is protected chemically from the lizard.

Broad-scale latitudinal patterns of genetic diversity among native European and introduced house sparrow (Passer domesticus) populations

Introduced species offer unique opportunities to study evolution in new environments, and some provide opportunities for understanding the mechanisms underlying macroecological patterns. We sought to determine how introduction history impacted genetic diversity and differentiation of the house sparrow (Passer domesticus), one of the most broadly distributed bird species. We screened eight microsatellite loci in 316 individuals from 16 locations in the native and introduced ranges. Significant population structure occurred between native than introduced house sparrows. Introduced house sparrows were distinguished into one North American group and a highly differentiated Kenyan group. Genetic differentiation estimates identified a high magnitude of differentiation between Kenya and all other populations, but demonstrated that European and North American samples were differentiated too. Our results support previous claims that introduced North American populations likely had few source populations, and indicate house sparrows established populations after introduction. Genetic diversity also differed among native, introduced North American, and Kenyan populations with Kenyan birds being least diverse. In some cases, house sparrow populations appeared to maintain or recover genetic diversity relatively rapidly after range expansion (<50 years; Mexico and Panama), but in others (Kenya) the effect of introduction persisted over the same period. In both native and introduced populations, genetic diversity exhibited large-scale geographic patterns, increasing towards the equator. Such patterns of genetic diversity are concordant with two previously described models of genetic diversity, the latitudinal model and the species diversity model.

A Basidiobolus sp. and its association with reptiles and amphibians in southern Florida

To provide information about the distribution of a Basidiobolus sp., an occasional pathogen in the subtropics and tropics, 95 reptiles and amphibians, comprising eight different species, were trapped from the beaches and inland habitats of Tampa and Miami, Florida. Five of the eight animal species were infested with Basidiobolus sp. Approximately 50% of the animals collected carried this zygomycete. Under laboratory conditions, it remained in the digestive tracts of some starved anoles for up to 3 weeks. Some animals, whose digestive tract was fungus-free, could be colonized with the Basidiobolus sp. by feeding them mealworms contaminated with propagules of this fungus. This finding alters, in a minor way, the present concept of the life history of the fungus.