三种抗凝血灭鼠剂对褐家鼠的实验室毒效比较

采用摄食试验方法,选用溴敌隆,杀鼠迷和敌鼠钠盐三种抗凝血灭鼠剂对褐家鼠进行实验室毒效比较。结果无选择摄食试验,溴敌隆,杀鼠迷和敌鼠钠盐三组的毒杀率均为１００％。有选择摄食试验,溴敌隆组珠毒杀率为９２．８６％,摄食系数是０．７０,毒饵接受性好,毒杀率高;杀鼠迷和敌鼠钠盐组毒杀率分别是６１．５４％３８．４６％,其摄食系数分别是０．４５,０．２２。     

两种鼠耳蝠回声定位叫声的比较

对鼠耳蝠属两种蝙蝠飞行状态下的声发射进行了比较研究.结果表明两种鼠耳蝠声发射信号的声谱图都呈调频(FM)型,但在波形及频率范围上有明显差异.大鼠耳蝠(四川亚种)的声脉冲宽度很小(1.6±0.3ms),能率环较低(4.0%),其主频率(DF=44.6±4.3kHz)也较低;而水鼠耳蝠的声脉冲宽度较大(4.2±1.6ms),能率环(9.6%)及主频率(DF=83.0±4.0kHz)也较高.文中结合两种蝙蝠的形态及食性分析了回声定位对捕食生境及捕食策略的适应性.     

Specific toxicity in six rodent species from China of a new modified norbormide

Norbormide (NRB) is a Rattus-specific toxicant that has low palatability and produces sub-lethal dosing in the field, thereby limiting its effectiveness as a rodent control tool. In this study, we assessed the species-specific effect and time to death of a lethal dose of a fatty acid derived pro-toxicant of NRB, named DR8, in six rodent species from China; three species of Rattus and three non-Rattus species. Our results showed three species/subspecies of Rattus were sensitive to DR8, with LD₅₀ values being less than 50?mg/kg, while non-Rattus rodent species were totally insensitive to this drug. As expected, the time to death in the three species of Rattus was longer in those rats dosed with DR8 compared to those dosed with NRB. This indicated that DR8 possesses a slower activity profile to NRB, and therefore supports its potential to increase palatability and be a promising species-specific tool for rodent pest management.

LSID?zoobank.org:pub:37372DC5-588E-4F39-8C25-A7A84AD7FE57     

On the evolution of group-living in the New World cursorial hystricognath rodents

We used the comparative method to examine the evolutionary causesof group-living in the New World cursorial hystricognath rodents.To do so, we used the available literature to collect informationon behavioral (group size, burrow digging), ecological (amountof plant cover in the habitat), and life history (body mass,time to sexual maturity) variables, along with phylogeneticrelationships of these rodents. We analyzed these variablesin the context of three major hypotheses. A first explanationposes that rodents live in groups to reduce the energy neededin the construction of their burrows. A second hypothesis suggeststhat grouped rodents increase their ability to detect and escapefrom predators. A third possibility states that group-livingis adopted by rodents to provide extra parental care to their offspring. Our comparative analysis revealed that across speciesvariation of group size is, to some extent, influenced by bodysize, and by the habit of burrow digging. Thus, large sizedrodent species that actively dig their own burrows form largergroup sizes than small sized species that do not dig burrows.In contrast, across species variation of group size was not influenced by differences in the amount of plant cover in thehabitat (an indirect measure of predatory risk), or by differencesin the time to first reproduction (a measure of parental caregiven). Therefore, group-living among the New World histricognathrodents seems more linked to a strategy aimed to reduce theirburrowing cost than to a strategy aimed to reduce their predatory risk, or to extend their parental investment.     

Do constructional constraints influence cichlid craniofacial diversification?

Constraints on form should determine how organisms diversify. Owing to competition for the limited space within the body, investment in adjacent structures may frequently represent an evolutionary compromise. For example, evolutionary trade-offs between eye size and jaw muscles in cichlid fish of the African great lakes are thought to represent a constructional constraint that influenced the diversification of these assemblages. To test the evolutionary independence of these structures in Lake Malawi cichlid fish, we measured the mass of the three major adductor mandibulae (AM) muscles and determined the eye volume in 41 species. Using both traditional and novel methodologies to control for resolved and unresolved phylogenetic relationships, we tested the evolutionary independence of these four structures. We found that evolutionary change in the AM muscles was positively correlated, suggesting that competition for space in the head has not influenced diversification among these jaw muscles. Furthermore, there was no negative relationship between change in total AM muscle mass and eye volume, indicating that there has been little effect of the evolution of eye size on AM evolution in Lake Malawi cichlids. The comparative approach used here should provide a robust method to test whether constructional constraints frequently limit phenotypic change in adaptive radiations.