The Cost of Male Aggression and Polygyny in California Sea Lions (Zalophus californianus)

In polygynous mating systems, males often increase their fecundity via aggressive defense of mates and/or resources necessary for successful mating. Here we show that both male and female reproductive behavior during the breeding season (June–August) affect female fecundity, a vital rate that is an important determinant of population growth rate and viability. By using 4 years of data on behavior and demography of California sea lions (Zalophus californianus), we found that male behavior and spatial dynamics—aggression and territory size—are significantly related to female fecundity. Higher rates of male aggression and larger territory sizes were associated with lower estimates of female fecundity within the same year. Female aggression was significantly and positively related to fecundity both within the same year as the behavior was measured and in the following year. These results indicate that while male aggression and defense of territories may increase male fecundity, such interactions may cause a reduction in the overall population growth rate by lowering female fecundity. Females may attempt to offset male-related reductions in female fecundity by increasing their own aggression—perhaps to defend pups from incidental injury or mortality. Thus in polygynous mating systems, male aggression may increase male fitness at the cost of female fitness and overall population viability

First documentation of leopard seal predation of South Georgia pintail duck

Leopard seals are regular winter visitors to Bird Island, South Georgia, where they mostly prey on fur seals and penguins, and to a lesser extent on Antarctic krill and fish. Leopard seals can exploit many different species, but there are no records of predation on flying shorebirds in the wild. On 4 October 2008, an individually identified juvenile leopard seal female was observed killing and eating a South Georgia Pintail duck. It also preyed on Antarctic fur seals and gentoo and macaroni penguins during its 2-month temporary residency around the island. The varied diet of this seal exemplifies the generalist prey utilization typical of its species. Long-term diet studies at Bird Island and the published record suggest that predation on ducks is a rather exceptional finding; individual ducks are more likely to escape leopard seal attacks than penguins and provide a far less substantial ration. This note documents the first observation of this species of duck in the diet of leopard seals

Major phytoplasma diseases of forest and urban trees

In the northern hemisphere, yellows, witches’ broom, and decline diseases of several forest and urban tree species are widespread and of considerable economic and ecological significance. Elm (Ulmus spp.) and alder (Alnus spp.) are affected by elm yellows (EY) and alder yellows (ALY), respectively. These diseases are mainly associated with the presence of closely related phytoplasmas, the EY agent ‘Candidatus Phytoplasma ulmi’ and the ALY agent, which are members of the EY or 16SrV group, subgroups 16SrV-A and 16SrV-C, respectively. Ash (Fraxinus spp.) is affected by ash yellows, a disease which occurs mainly in North America and is associated with the presence of ‘Candidatus Phytoplasma fraxini’, a member of subgroup 16SrVII-A. Poplar (Populus spp.), sandal (Santalum album), paulownia (Paulownia spp.), and mulberry (Morus spp.) are affected by yellows diseases associated with phytoplasmas of different 16SrI subgroups. Several species of conifers are affected by yellows and witches’ broom diseases associated with phytoplasmas belonging to at least five taxonomic groups (16SrI, 16SrIII, 16SrVI, 16SrIX, and 16SrXXI) and several different subgroups. A number of urban tree species grown in the Sabana de Bogotà (Colombia) are affected by decline diseases which are primarily associated with 16SrI and 16SrVII phytoplasmas. This chapter summarizes the current knowledge of major phytoplasma diseases of forest and urban trees grown in the northern hemisphere