Flying distance of frass kicked by the grasshopper Atractomorpha lata and factors affecting the flying distance

Adults of the grasshopper Atractomorpha lata use a hind leg kick to project their frass a considerable distance from themselves. To clarify the defecation behavior quantitatively and collect basic information that aids in clarification of the adaptive significance of this behavior, we measured the flying distance of kicked frass and examined the factors affecting the flying distance in adult A. lata. Males and females kicked their frass an average of 252 and 487 mm away, respectively. This represented more than ten times the body length or 100 times the length of the frass pellet for either sex. Only sex affected the flying distance of frass. There were sexual differences in hind‐femur length (females longer than males), volume of frass pellet (females larger than males) and ratio of diameter to length of frass pellet (RFP; larger in males than in females). The flying distance appears to be affected by the femur length, volume of frass pellet and RFP when data of both males and females were combined for analysis. However, none of these effects were observed when testing the effects within each sex. These results suggest that the sex difference in the flying distance does not result from the sex difference in femur length, volume of frass pellet or RFP. Because A. lata kicked their frass far away in both sexes, the frass‐kicking behavior might give benefit common to both males and females.     

Body Size and Multiple Copulations in a Neotropical Grasshopper with an Extraordinary Mate-Guarding Duration

After copulation, male grasshoppers of Sphenarium purpurascens (Orthoptera: Pyrgomorphidae) remain in a postinsemination association with their mate. A male can spend as many as 17 days mounted on a female. Guarding duration is related to both male and female body size and the female's mating history. Longest guarding durations were recorded at the middle of the reproductive season, when the probability of encounter between the sexes (sex ratio and population density) was decreasing, at the beginning of the associated dry season. These guardings were associated with large individuals of both sexes and with females that had more previous partners. Moreover, a positive association was found among guarding duration, female and male body size and age, and number of copulations performed by the males. Maybe males invest time and sperm in females as a function of the probability of sperm competition. Nevertheless, guarding may provide benefits to both sexes. Males may reduce the possibility of sperm competition, and females may obtain nutritional benefit for themselves or their offspring as a result of multiple copulations. Changes in male investment in guarding duration and number of copulations may be the result of physiological constraints related to seminal and/or sperm production. Moreover, guarding duration could be constrained by ecological factors such as a reduction of food availability associated with the beginning of the dry season.     

短额负蝗线粒体基因组及其lrRNA和srRNA二级结构分析

采用长距PCR扩增及保守引物步移法测定并注释了短额负蝗的线粒体基因组全序列。结果表明,短额负蝗的线粒体基因组全长15558bp,A T含量为74.3%,37个基因位置与飞蝗的一致,基因间隔序列共计11处64bp,间隔长度从1～16bp不等;有15对基因间存在51bp重叠,重叠碱基数在1～8bp之间。13个蛋白质编码基因中找到6种可能的起始密码子,有12个基因在基因3'端能找到完全的TAA或TAG终止密码子,只有ND5基因终止密码子为不完整的TA。除tRNASer(AGN)外,其余21个tRNA基因的二级结构均属典型的三叶草结构。tRNASer(AGN)的DHU臂缺失,在相应的位置上只形成一个环。预测的lrRNA二级结构总共有6个结构域(结构域Ⅲ缺失),49个茎环结构。预测的srRNA的二级结构包含3个结构域,33个茎环结构。A T丰富区中存在一个被认为与复制及转录起始有关的Ploy(T)(T-stretch)结构。     

中国瘤锥蝗科和锥头蝗科的支序系统学研究

通过比较中国分布的瘤锥蝗科Chrotogonidae和锥头蝗科Pyrgomorphidae10属蝗虫的形态学性状,选择了22个性状对10属蝗虫的系统发育关系进行支序系统学分析。结果表明：从支序图来看这10个属的关系相互交织在一起,不能区别为两个科。笔者建议在蝗虫分类系统中,把锥头蝗科和瘤锥蝗科合在一起作为一个科比较妥当。     

The role of body size in mating success of Sphenarium purpurascens in Central Mexico

1. The effect of body size on the assortative mating and reproductive behaviour of the univoltine grasshopper Sphenarium purpurascens (Charpentier) was studied in Central Mexico. 2. Assortative mating by size was observed in the field. Evidence of positive assortative mating in relation to body size was found in laboratory experiments. Female fecundity and male success in contests were also correlated with body size. 3. Larger females had a higher number of eggs per pod. Larger males usually won fights and were able to take over females from other males, and to resist takeovers by other males while guarding. 4. Individuals of both sexes were observed copulating with more than one sexual partner in the field, suggesting polygamy. Male–male contests determined access to females, and males exhibited a postcopulatory prolonged mate-guarding behaviour lasting up to 18 days. 5. In a 2-year study, sex ratio was male-biased at the beginning of the reproductive season and decreased to 1:1 by the end of the season, suggesting that the population is protandrous. 6. The results of this study indicate that assortative mating results from male–male competition and female availability, and suggests that body size is a potential target of natural and sexual selection.     

Two new species of grasshopper from China (Orthoptera:Pyrgomorphidae)

The genus Chlorizeina Brunner von Wattenwyl, 1893 is firstly recorded for China. Two new species, Chlorizeina yunnana sp. nov. and Tagasta nigritibia sp. nov. are reported from China. All specimens are deposited in the Biological Science Museum, Dali University(BMDU).