Responses, Ecological Effects And Hereditary Studies Of Reproductive Endocrine Rhythms Of Asian Short - Toe Braun To Climate Warming

Climate change is considered to be the greatest threat to global biodiversity. Under the background of global warming, the climate of our country has changed significantly in recent years, especially in the northeast of China and Inner Mongolia. Due to the increasing of temperature, the development of insects could advance, while the initiation of bird reproduction induced by the light period could not advance, which has resulted in the phenology mismatch between the bird and insect. Therefore, it is necessary to understand the possibility of birds advance the start of the reproductive endocrine and then shift the reproductive behavior to an earlier date in order to keep up with the development of insects in high temperature conditions. Whether reproductive endocrine plasticity can make Asian short-toed lark nestlings hatched inside the peak period of nymph abundance? Whether reproductive endocrine rhythm is regulated by the genetic and help the birds adapt to the phenological mismatch through microevolution? Whether phenologyical mismatch will influence on bird populations?We take the interaction relations of the Asian short-toed lark and locust as a case to study the synchronism between the reproduction rhythm of passerine birds and insect development in grassland ecosystem. Luteinizing hormone (LH), Testosterone(T) and Estradiol(E2)are used as indicators to study the temperature plasticity among individuals of HPG axis secretion rhythm of the Asian short-toed lark. We also analyze the relationship between HPG axis secretion rhythm and Clock genes, and the adaptation mechanisms of birds on phenological mismatch. The main results are as follows:1. The locust nymphs’ first appear date and biomass peak date, birds’ first hatching date and hatching peak date in high temperature year were all earlier than those in low temperature year. The nestlings hatching peak of Asian short-toed lark mismatched locust nymphs biomass peak in high temperature year, while matched in low temperature year. The Asian short-toed lark’s reproductive success rate in high temperature year was much lower than that in low temperature year. The survival rate of the chicks hatching inside the nymph biomass peak period was higher than the chicks hatching outside the nymph biomass peak period. The above results show that the rising temperature can make the reproductive behavior of Asian short-toed lark ahead of time, but the development of locusts advance faster in high temperature, so the high temperature result in the mismatch of the nestlings hatching peak of Asian short-toed lark and locust nymphs biomass peak. The chicks mismatched the larvae peak is weak than those matched.2. The Asian short-toed lark’s LH and T levels in 2014 were significantly higher than those in 2015. The date of population’s mean value of LH and T levels that reached the peak in 2014 were six days in advance than 2015. The female’s E2 level has no significant difference between 2014 and 2015, but its mean value peak date in 2014 was 12 days in advance than 2015. The concentrations of LH and T in high temperature group were significantly higher than those in low temperature group. The mean value peak date of LH and T levels in high temperature group were 4 days ahead of low temperature group. While the E2 levels of the two groups did not show significant differences, but the time of the high temperature group reached the peak was 4 days in advance than low temperature group. Above results show the reproductive endocrine of Asian short-toed lark start with plasticity response to temperature changes.3. The Asian short-toed lark with fewer poly-Q repeats to reach reproductive hormone peak value earlier, and it had obvious gender differences: male’s reproductive hormone reached peak value earlier than female. Male’s reproductive hormone peak deviation amplitude has no difference under different temperatures, but female’s reproductive hormone peak deviation amplitude under high temperature was greater than that under low temperature. Above results show that the reproductive endocrine of Asian short-toed lark started differences owing to a certain genetic basis.