Animal Ecology and Behavior Studies

The Population Biology of Invasive Species

▪ Abstract Contributions from the field of population biology hold promise for understanding and managing invasiveness; invasive species also offer excellent opportunities to study basic processes in population biology. Life history studies and demographic models may be valuable for examining the introduction of invasive species and identifying life history stages where management will be most effective. Evolutionary processes may be key features in determining whether invasive species establish and spread. Studies of genetic diversity and evolutionary changes should be useful for understanding the potential for colonization and establishment, geographic patterns of invasion and range expansion, lag times, and the potential for evolutionary responses to novel environments, including management practices. The consequences of biological invasions permit study of basic evolutionary processes, as invaders often evolve rapidly in response to novel abiotic and biotic conditions, and native species evolve in response to the invasion.

Population biology of infectious diseases: Part I

Progress in invasion biology: predicting invaders

The Social Structure and Reproductive Biology of Colonies of the Mole-Rat, Cryptomys damarensis (Rodentia, Bathyergidae)

Cryptomys damarensis occurs in semiarid regions of southwestern and central Africa. It lives in colonies in which reproduction is restricted to one or two of the largest-sized males and the largest female in the colony. Some division of labor, into frequent and infrequent workers, occurs within the remaining colony members. Reproduction and details of colony size and the number of breeding animals in a colony are described for two complete and five incomplete wild-captured colonies; one of the complete colonies and mole-rats from the incomplete colonies were maintained in captivity for more than 2 years. The breeding female initiated precopulatory behavior, mating occurred for about 2 weeks, the gestation length was 78–92 days, mean litter size was 2.8 (n = 10), and a maximum of four pups was born. The pups were precocial, wandered out of the nest within 24 h after birth, began to eat solids when 6 days old, and were fully weaned when 3 weeks old. When 6 weeks old, pups began to spar with each other and with some colony members, but levels of aggression were never high and the pups were incorporated into the colony. In the colony, subordinate and frequent-worker mole-rats weighed less than dominant animals and infrequent workers; mass, therefore, was not necessarily indicative of the age of the animal. During the 2-year study period, three mole-rats that were frequent workers on capture changed their castes to infrequent workers, two of them showed a concomitant increase in body mass. The colony structure and reproduction of C. damarensis are compared with those of the eusocial Heterocephalus glaber.