Habitat fragmentation: island v landscape perspectives on bird conservation

Fragments of habitat are often viewed as islands and are managed as such; however, habitat fragmentation includes a wide range of spatial patterns of environments that may occur on many spatial scales. Fragments exist in a complex landscape mosaic, and dynamics within a fragment are affected by external factors that vary as the mosaic structure changes. The simple analogy of fragments to islands, therefore, is unsatisfactory. Understanding how birds respond to these complexities of fragmentation requires mechanistic studies focused on habitat selection and movement behaviour. Conservation efforts must be based on viewing fragmentation as a range of conditions that occurs in a landscape mosaic, and management should be directed toward the mosaics rather than focusing solely on reserves.     

Complete Elimination of Mitosis and DNA Synthesis in the Lens of the Hypophysectomized Frog: Effects on Cell Migration and Fiber Growth

Three weeks after hypophysectomy mitosis and DNA synthesis are absent in the lens of the leopard frog ( Rana pipiens ). By labeling germinative zone cells in their last DNA synthetic period we were able to follow them in the absence of further proliferation. By this means it has been demonstrated that migration of epithelial cells to the equator of the lens is stopped. Based on indirect measurements it seems that lens fiber formation also ceases. A correlation coefficient of 0.86 was computed between average labeling index and average distance migrated. In hypophysectomized animals the correlation coefficient between time and migration was 0.02 while in intact animals it is 0.87.     

Isolation of highly polymorphic microsatellite markers from the intertidal barnacle Chthamalus montagui Southward

This study reports the isolation and characterization of seven highly polymorphic microsatellite loci in Chthamalus montagui (Crustacea, Cirripedia). The loci were isolated from a library constructed from genomic DNA enriched for CA repeats. The markers yielded three to 43 alleles per locus (mean 16.7) in samples averaging 49 individuals. Observed heterozygosity ranged from 0.08 to 0.58 (mean 0.39). These microsatellite loci will be valuable tools for population genetic studies of this species.     

An orb‐weaver spider eludes plant‐defending acacia ants by hiding in plain sight

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Mating behavior and genitalic counterparts in tiger beetles (Carabidae: Cicindelinae)

Comparative studies on the structure of genitalia in Pseudoxychila tarsalis Bates and the copulating behavior in 5 species of Cicindela respectively complement similar findings by Freitag [1] on Cicindela spp. and Palmer [4] on P. tarsalis. These strengthen the hypothesis that in tiger beetles the flagellum fits into the spermatheca duct during copulation; that the main function of the flagellum, which is closed at the apex and not connected to the ejaculatory duct, is to open and prepare the lumen of the spermatheca duct for sperm movement from the bursa copulatrix to the spermatheca; and that copulation proceeds in 3 phases: phase 1 in which the lumen of the spermatheca duct is cleared by the flagellum, phase 2 in which the flagellum is withdrawn from the spermatheca duct, and phase 3 in which semen is transferred from the gonopore of the ejaculatory duct to the bursa copulatrix, usually with a spermatophore.