Isolation and characterization of microsatellite loci in the flat‐headed bat (Tylonycteris pachypus)

Microsatellite loci were developed in the flat‐headed bat (Tylonycteris pachypus) from genomic DNA using an enriched library method. Nine loci were tested on 48 individuals sampled from Guangxi Province, China. The mean number of observed alleles per locus was 6.4 (range 4–12). Observed and expected heterozygosity values ranged from 0.24 to 0.83 and from 0.30 to 0.89, respectively. One locus revealed significant departure from Hardy–Weinberg equilibrium and no significant linkage disequilibrium was detected between loci pairs. These markers will be used to examine genetic structure and parentage analysis in this species.     

Hierarchical polygyny in multiparous lesser flat-headed bats

How males gain access to mates and the potential for female choice will determine whether polygyny can operate at several levels, from within litters and groups to the wider population. Female lesser flat-headed bats (Tylonycteris pachypus) form maternity groups in bamboo stems. Unusually for bats, they are multiparous, providing the opportunity to test whether multi-level polygyny differs among males depending on whether they roost with females, with males or are solitary. We genotyped 662 individuals from 54 internodes and analysed parentage of 165 litters. Our results revealed 170 sets of paternal twins/triplets, of which 96 were full-sibs and 74 were half-sibs. We found that males captured roosting with females typically sired more offspring overall than did other males and also showed a greater tendency to monopolize paternity within both litters and roosting groups. In comparison, males that sired fewer full-sibs were assigned more maternal half-sibs. These latter individuals, which included solitary males and those from all-male groups, might gain copulations either via roaming with furtive mating or during visits by females. Indeed, female lesser flat-headed bats store sperm, so could benefit from multiple mating to reduce genetic incompatibilities. At the same time, however, we found no evidence of outbreeding. Finally, relatedness and mtDNA analyses revealed that polygyny also operated within matrilineal kin, suggesting a system that might promote social cohesiveness. Future studies of individual movements will help to determine the extent to which mixed paternities in litters, matrilines and groups are driven by male or female behaviour.     

扁颅蝠与褐扁颅蝠的集群结构

2001—2002年在广西宁明县和龙州县利用直接观察、捕捉测量(共捕到197群蝙蝠,全捕180群)和标记重捕法(标记了31群的101只扁颅蝠,重捕到36只)比较研究了扁颅蝠(tylonycteris pachypusa)与褐扁颅蝠(T．robustula)的集群结构。结果发现：扁颅蝠与褐扁颅蝠主要栖宿在刺竹(Bambusa stenostachya)的竹筒内,通过竹筒上的裂缝进出。扁颅蝠栖宿的竹筒长平均为27．7cm,外围直径平均为23．6cm;褐扁颅蝠的分别为28．3cm和23．8cm。扁颅蝠栖宿群大小为1—24只,褐扁颅蝠栖宿群大小为1—13只;2种蝙蝠的栖宿群中皆为独居所占比例最大(扁颅蝠为22．30％,褐扁颅蝠为40．63％),2只所占比例次之(分别为14．87％和18．75％),其它大小类型呈不规则变化。扁颅蝠栖宿群的性别组成,以雌雄混居最常见(占54．72％),其次为独居雄性(占20．95％),而褐扁颅蝠栖宿群雌雄混居群与独居雄性所占比例相当(均为40．63％)。2种蝙蝠的雄性趋向于独居,而雌性趋向于群居。扁颅蝠与褐扁颅蝠可以栖宿在同一片竹林内,并且可以在不同时间轮流使用同一个栖宿竹筒,但2种蝙蝠从未共栖于同一个竹筒内。另外,标记重捕扁颅蝠发现：扁颅蝠经常变换栖宿竹筒(栖宿竹筒不固定);同时栖宿群之间经常发生个体交换[动物学报50(3)：326—333．2004]。     

The role of olfactory cues in mother–pup,groupmate, and sex recognition of lesser flat‐headed bats,Tylonycteris pachypus

Tylonycteris pachypus is a gregarious bat species with tens of individuals in a colony. The mechanisms by which mother bats recognize their pups and adult bats recognize each other are not clear. We hypothesized that such recognition is achieved by chemical discrimination and performed experiments to test the hypothesis. Results showed that mother bats were much more attracted to the scent from their own pups. For adult bats, females were attracted to the scent from both male and female groupmates but had a higher preference to the scent from female than from male groupmates. Male bats were much more attracted to the scent from male groupmates while showed no preference to the scent from female groupmates. Within a group, both female and male bats had no difference in preference to the scent from the same or opposite sex. These results suggest that mother–pup and groupmate recognition of T. pachypus can be achieved by olfactory cues.     

两种扁颅蝠回声定位叫声的比较

对扁颅蝠 (Tylonycterispachypusa)和褐扁颅蝠 (T robustula)在飞行状态下的回声定位叫声进行了比较研究。结果表明 ,2种扁颅蝠的回声定位叫声的声谱图均呈调频 (FM)型 ,且波形相似 ;但叫声的最低频率、最高频率和主频率差异极显著 (P <0 0 1)。扁颅蝠的频率范围较高 ,为 6 2 4～ 91 6kHz ,主频率为 (76 5± 2 1)kHz ;褐扁颅蝠的频率范围较低 ,为 4 2 7～ 72 4kHz ,主频率为 (49 2± 1 8)kHz ;而 2种蝙蝠的声脉冲时程、声脉冲间隔和声脉冲重复率差异不显著 (P >0 0 5 )。回声定位叫声差异与其体型、所处的生境有关     

Development and characterization of 13 novel microsatellite loci from the flat-headed bat (Tylonycteris pachypus) with cross-species amplification in closely related taxa

13 novel microsatellite loci was isolated using the enriched library method from genomic DNA of the flat-headed bat (Tylonycteris pachypus). These loci showed high levels of genetic polymorphism testing on 54 individuals sampled from Guangxi province, China. The number of observed alleles per locus ranged from 2 to 15. The expected and observed heterozygosity values ranged from 0.170 to 0.900 and from 0.185 to 0.944, respectively. One loci departed significantly from Hardy-Weinberg equilibrium (HWE) after Bonferroni correction and no Linkage disequilibrium was found between any pairs of loci. In addition, these loci were tested in the sister species, Tylonycteris robustula, seven loci amplified successfully and were also polymorphic.     

扁颅蝠的栖息地及最北分布

扁颅蝠(Tylonycteris pachypus)被列入《中国濒危动物红皮书》,是我国最小的蝙蝠之一。因其栖息于竹子中的特殊习性而备受人们关注。研究显示,扁颅蝠选择有虫蚀的粉单竹(Lingnania chungin)竹林栖息(洞口平均为43.79 mm×11.94 mm)。1997年8月在四川南充市金城山(N30°40′,E106°18′)发现的扁颅蝠,为其地理上最北分布。     

广西扁颅蝠与褐扁颅蝠的食物选择

2002年3～10日在广西南宁地区的宁明县和龙州县,用超声波监测和网捕法确定扁颅蝠与褐扁颅蝠的捕食区,在捕食区内用粘捕法调查潜在的食物量;用粪便分析法确定食物组成。在宁明县和龙州县扁颅蝠和褐扁颅蝠的潜在食物量都是以双翅目昆虫为主(45．93％以上),其次为鞘翅目(12．59％以上)和膜翅目(7．47％以上);但双翅目、膜翅目在两地差异显著。宁明县扁颅蝠的食物组成以双翅目(40．33％)和膜翅目(38．46％)为主,鞘翅目(16．07％)次之;龙州县扁颅蝠和褐扁颅蝠食物组成中以膜翅目(63．37％,62．34％)为主,其次为双翅目(21．57％,29．62％)、鞘翅目(11．59％,5．96％);对比两地扁颅蝠的食物组成发现,膜翅目和双翅目差异极显著。对比食物组成与潜在食物量发现,两种蝙蝠对膜翅目为正选择,对其他目负选择或无选择,均为选择性捕食者。     

Morphology, echolocation and foraging behaviour in two sympatric sibling species of bat (Tylonycteris pachypus and Tylonycteris robustula) (Chiroptera: Vespertilionidae)

We studied the wing morphology, echolocation calls, foraging behaviour and flight speed of Tylonycteris pachypus and Tylonycteris robustula in Longzhou County, South China during the summer (June–August) of 2005. The wingspan, wing loading and aspect ratio of the two species were relatively low, and those of T. pachypus were lower compared with T. robustula . The echolocation calls of T. pachypus and T. robustula consist of a broadband frequency modulated (FM) sweep followed by a short narrowband FM sweep. The dominant frequency of calls of T. pachypus was 65.1 kHz, whereas that of T. robustula was 57.7 kHz. The call frequencies (including highest frequency of the call, lowest frequency of the call and frequency of the call that contained most energy) of T. pachypus were higher than those of T. robustula , and the pulse duration of the former was longer than that of the latter. The inter-pulse interval and bandwidth of the calls were not significantly different between the two species. Tylonycteris pachypus foraged in more complex environments than T. robustula , although the two species were both netted in edge habitats (around trees or houses), along pathways and in the tops of trees. Tylonycteris pachypus flew slower (straight level flight speed, 4.3 m s⁻¹) than T. robustula (straight level flight speed, 4.8 m s⁻¹). We discuss the relationship between wing morphology, echolocation calls, foraging behaviour and flight speed, and demonstrate resource partitioning between these two species in terms of morphological and behavioural factors.     

Brains of Vespertilionids II. Vespertilioninae with special reference to Tylonycteris

As shown in Part I, the Vespertilioninae have on the average the lowest encephalization index (EI) of all the Vespertilionid subfamilies available, and the average size indices (Sis) of most of their brain parts are also lowest. There are, however, clear differences between the genera. The highest indices for the total brain and for many brain parts (OBL, DIE, TEL, PAL, SEP, STR, SCH) were found in Myotis, the highest Sis for NEG and MES in Scotophilus, for CER in Lasiurus, for BOL in Rhogeessa, and for HIP in Cbalinolobus. The lowest values for all brain parts except BOL were found in Tylonycteris (for BOL in Glauconycteris). The average EI of the flat-headed bamboo bats Tylonycteris pachypus and T. robustula was 60, i. e., ²/₅ less than that of the non-Tylonycteris Vespertilionids, which, as the reference group, have an average EI of 100. The brain size reduction may well be related to the adaptation to extreme flat-headedness. The amount of reduction in the various brain parts differs: it is strongest (about ¹/₂) in higher but more dispensable brain parts (STR, HIP, NEO) and distinctly lower (about ¹/₄) in structures closely involved in the fundamental vegetative functions (OBL, MES). Genera with conservative skull characteristics may have derivative characteristics of the brains, and vice versa.