Long-term video and genetic data yield insights into complex sociality of a solitary large carnivore.

American black bears (Ursus americanus) may be more social than currently understood. We used long-term video and genetic data to evaluate social interactions among wild, independent-aged black bear on a conservation property in western Montana, USA. We used multinomial logistic regression to evaluate predictions about male-male interactions within the context of individual fitness, female-female interactions within the context of inclusive fitness, and male-female interactions within the context of female counterstrategies to infanticide. Overall, our findings challenged the assumption that independent-aged bears interact only during the mating season or when concentrated feeding sites are present. We documented 169 interaction events by at least 66 bear pairs, 92 (54%) of which occurred outside of the peak mating season and in the absence of concentrated feeding sites. The probability that male-male pairs engaged in play and other non-agonistic behaviours was higher than that for female-female pairs. Conversely, the probability that female-female pairs engaged in chase behaviour was higher than that for male-male and male-female pairs. We documented evidence of female mate choice, female resource defense, sexually selected infanticide (SSI), and female counterstrategies to avoid SSI. Our findings improve our understanding of ursid ethology and underscore the complexity of ursid sociality.

Isolation and characterisation of tilapia beta-actin promoter and comparison of its activity with carp beta-actin promoter.

The regulatory sequence including proximal promoter, untranslated exon 1 and intron 1 of the beta-actin gene from tilapia (Oreochromis niloticus) has been isolated and spliced to a beta-galactosidase reporter gene to test its activity. Comparisons of promoter activity have been carried out with three different constructs: (1) 1.6 kb tilapia beta-actin regulatory sequence, (2) 1.5 kb carp beta-actin regulatory sequence, and (3) 4.7 kb carp beta-actin regulatory sequence. Although the 1.6 kb tilapia beta-actin regulatory sequence gave slightly different expression patterns in tilapia embryos assayed by in situ X-gal staining, no difference was observed in expression level when the tilapia sequence was compared with the 4.7 kb carp beta-actin regulatory sequence by quantitative assay. In comparison with the 1.5 kb carp beta-actin regulatory sequence, the 1.6 kb tilapia beta-actin regulatory sequence gave higher expression levels in tilapia embryos, while a reverse result was observed in zebrafish embryos. In cell transfection experiments, the 1.6 kb tilapia beta-actin regulatory sequence showed three to four times better activity in blue gill cells than either the 4.7 kb carp beta-actin or the 1.5 kb carp beta-actin regulatory sequences. The 1.6 kb tilapia beta-actin regulatory sequence also drove higher reporter gene activity in somatic cells of tilapia than did the 4.7 kb carp beta-actin regulatory sequence following direct injection of constructs into muscle. Therefore, taken together, the data demonstrate that the tilapia beta-actin promoter can be used as an efficient regulatory sequence to produce autotransgenic tilapia.