Habitat destruction may lead to highly female-biased sex ratios

Local mate competition(LMC) was firstly used to explain extra-ordinary female-biased sex ratios. However, some observations have found that the sex ratios of some species are more female-biased than the predictions of LMC and its extensions; there is not yet a theory that accounts for the mechanisms of more female-biased sex ratio. Here, we assume that LMC occurs at a destructed habitat that reduces the resource for production, and present a new extension for the LMC model. Consequently, our model shows that the evolutionarily stable strategy(ESS) for sex ratio depends on two parameters: the number of foundresses and the degree of habitat destruction. Moreover, the sex ratio decreases as the degree of habitat destruction increases, i.e., the proportion of female increases. These results generally agree with experimental data, and may provide a new basis for the evolution of female-biased sex ratios in local mate competition and a new theory support for conservation of some species.

Local Governments’ Tax Competition, Industrial Structure Adjustment and Regional Green Development in China

Based on the inter-provincial panel data from 200 to 2014 in China,this paperapplies the spatial panel simultaneousequations model to test the impact of localgovermments'tax competition and industrial structure adjustment on the regionalgreen development in China.The conclusions are as follows.Local govermments'tax competition and industrial development have a negative impact on greendevelopment.Tax competition and industrialization in the neighboring regions willalso suppress local green development through the negative incentives of"race to thebottom",Evidently,regulating the tax competition behavior of the local governmentand rationally guiding the upgrading of local industrial structure have importantpolicy implications for the high-quality growth of China's regional economy and thegreen,coordinated development between regions in the new era.

Pollinating fig wasp Ceratosolen solmsi adjusts the offspring sex ratio to other foundresses

Local mate competition theory predicts that offspring sex ratio in pollinating fig wasps is female-biased when there is only one foundress, and increased foundress density results in increased offspring sex ratio. Information of other foundresses and clutch size have been suggested to be the main proximate explanations for sex ratio adjustment under local mate competition. Our focus was to show the mechanism of sex ratio adjustment in a pollinating fig wasp, Ceratosolen solmsi Mayr, an obligate pollinator of the functionally dioecious fig, Ficus hispida Linn., with controlled experiments in the field. First, we obtained offspring from one pollinator and offspring at different oviposition sequences, and found that offspring sex ratio decreased with clutch size, and pollinators produced most of their male offspring at the start of bouts, followed by mostly females. Second, we found that offspring sex ratio increased with foundress density, and pollinators did adjust their offspring sex ratio to other females in the oviposition patches. We suggest that when oviposition sites are not limited, pollinators will mainly adjust their offspring sex ratio to other foundresses independent of clutch size changes, whereas adjusting clutch size may be used to adjust sex ratio when oviposition sites are limited.