利用微卫星标记分析东平湖黄颡鱼的遗传多样性

采用27对鲤微卫星引物对山东东平湖黄颡鱼进行全基因组扫描,结果有19对引物能获得稳定的扩增条带,其中有6个微卫星位点具有多态性。对这6个位点的扩增产物进行分析,结果显示:6个位点共检测到22个等位基因,每个位点的等位基因数从2个到6个不等;平均基因纯合率为41.67%,平均多态信息含量(PIC)为0.488,平均杂合度为0.5833。这表明东平湖黄颡鱼种群结构合理,群体遗传多样性较丰富,种质资源处于安全状态。     

LOW FREQUENCY NARROW-BAND SOUNDS PRODUCED BY BOTTLENOSE DOLPHINS

We present a new sound type recorded from bottlenose dolphins, Tursiops truncatus , in eastern Australian waters: low-frequency, narrow-band (LFN) harmonic sounds (defined as less than 2 kHz). Most of these sounds were of frequencies less than 1 kHz and were recorded commonly from socializing dolphins. These sounds differ significantly from narrow-band whistles, which are higher in frequency and longer in duration. The absence of these sounds in most studies of the acoustic behavior of bottlenose dolphins may reflect geographic differences in repertoires or result from insufficient sampling. Alternatively, these sounds may have been ignored where the focus of research was on other sound types.     

Association between burst-pulse sounds and aggressive behavior in captive Atlantic bottlenosed dolphins (Tursiops truncatus)

A specific display observed during agonistic behavior among captive Atlantic bottlenosed dolphins (Tursiops truncatus) was examined. The primary component of the display was an open-mouthed posture accompanied by violent vertical head motions and the emission of pulse-type vocalizations. Jaw-clap behavior produced during the display was quantified for use as an index of aggressive motivation. By aurally monitoring the animals' vocalizations it was found that the level of aggressive response between the participants of the interactions increased with the production and subsequent duration of burst-pulse sounds. The possibility of burstpulse sounds resulting in auditory or tactile discomfort when directed toward conspecifics is discussed.     

Electrophoretic analysis of the prey spectrum of Teretrius nigrescens (Lewis) (Col., Histeridae), a predator of Prostephanus truncatus (Horn) (Col., Bostrichidae), in Mexico, Honduras, and Benin

Abstract: Extensive collections of Teretrius nigrescens in Mexico, Honduras, and Benin, were electrophoretically analysed to elucidate the prey spectrum of the predator. Both polyacrylamide gel electrophoresis and cellulose acetate electrophoresis were used. Beetles were sampled with pheromone traps, using the synthetic aggregation pheromone of Prostephanus truncatus , and directly from farmers' maize stores. The proportion of electrophoretically detected prey protein from adult T. nigrescens in pheromone traps was low: of the 1108 specimens analysed, only in 34 cases, prey protein could be clearly identified. More frequently, prey protein was detected in adult T. nigrescens sampled in maize stores in Mexico, Honduras, and Benin, with 87 samples showing distinct prey bands of the total 1214 predators analysed. Of the 241 T. nigrescens larvae sampled in maize stores in Benin, 136 showed distinct bands of prey protein. In all samples, P. truncatus was the most frequently detected prey species. The second most often identified prey species was Sitophilus zeamais . The results are discussed with regard to various methods for prey spectrum analysis and specifically the biology of T. nigrescens .     

LATERAL MANDIBULAR WALL THICKNESS IN TURSIOPS TRUNCATUS: VARIATION DUE TO SEX AND AGE

In odontocetes the mandibular bone serves two functions: to capture prey, and as a means of the reception and transmission of sound waves through a fat body in the mandibular canal, which opens posteriorly as the mandibular foramen. The posterior part of the lateral wall of the odontocete mandible is thin, and appears to represent a compromise between a strong mandible for prey capture and a thin vibrating plate for hearing. We studied the intraspecific variation of minimum thickness of the lateral mandibular wall along four transects (T1-T4) at the area of the mandibular foramen, in relation to the skull size and the mandibular size in different-aged bottlenose dolphins, Tursiops truncatus (18 females between 1 and 42 yr, 17 males between 1 and 32 yr). The minimum thickness was absolutely at its lowest at the most posterior transect T1, but did not vary significantly between the sexes or between the ages. The minimum thickness varied significantly at the two most anterior transects, T3 and T4, both between the sexes and among the ages. The thickness increased throughout life among males, whereas in females it first increased and then starts to decrease around the age of 20.     

Trees or stores? The origin of migrating Prostephanus truncatus collected in different ecological habitats in southern Benin

Migrating Prostephanus truncatus (Horn) (Col.: Bostrichidae) were collected weekly with pheromone-baited funnel traps at three different sites in southern Benin for 12 months. One site was located in a primary forest, one in a peri-urban area, and one in a region with intensive agriculture. The sex of the trapped beetles was determined. The gut-content of the specimens was analyzed for remains of lignin and starch, the former indicating recent feeding on woody, the latter on a starchy substrate, such as stored maize or dried cassava. At all locations, the sex ratio of migrating P. truncatus was significantly female-biased, with the greatest proportion of females trapped at the peri-urban site. At the forest site, most beetles had lignin in their guts, while the proportion of beetles containing starch was highest in the peri-urban site. Approximately equal proportions of beetles with either starch and lignin were trapped in the region with intensive agriculture. The results are discussed with regard to the population dynamics of P. truncatus in different habitats and the flight activity of the beetles.     

Visual-only assessments of skin lesions on free-ranging common bottlenose dolphins (Tursiops truncatus): Reliability and utility of quantitative tools

Photo analysis offers a simple, noninvasive approach to characterizing and quantifying skin lesions in cetaceans; however, this process involves methodological considerations that have often gone unaddressed or have varied in approach among investigators. Subjectivity associated with classifying skin lesion types of unknown etiology and quantifying measures of skin lesion prevalence and extent from photo data raises questions about observer bias and agreement (i.e., interrater reliability), which are often ignored. The purpose of the present study was to improve upon data quality control and assessment practices when studying skin lesions using only photo data. Specifically, we tested interrater reliability of a skin lesion classification system, compared methods of quantifying skin lesion extent, and determined the validity of the dorsal fin as a proxy for skin lesions on the entire body. Acceptable levels of interrater reliability were achieved for only 7 of 17 defined lesion types, but reliability was high for the two tested measures of lesion extent. Skin lesion extent measured from the dorsal fin alone was not a decent proxy for the whole visible surface; disparities between measures were as high as 43%. We discuss the potential pitfalls discovered and provide recommendations for others attempting similar approaches.     

Epidemiology of tattoo skin disease in captive common bottlenose dolphins (Tursiops truncatus): Are males more vulnerable than females?

Clinical and epidemiological features of tattoo skin disease (TSD) are reported for 257 common bottlenose dolphins held in 31 facilities in the Northern Hemisphere. Photographs and biological data of 146 females and 111 males were analyzed. Dolphins were classified into three age classes: 0–3 years, 4–8 years, and older than 9 years. From 2012 to 2014, 20.6% of the 257 dolphins showed clinical TSD. The youngest dolphins with tattoo lesions were 14 and 15 months old. TSD persisted from 4 to 65 months in 30 dolphins. Prevalence varied between facilities from 5.6% to 60%, possibly reflecting variation in environmental factors. Unlike in free-ranging Delphinidae, TSD prevalence was significantly higher in males (31.5%) than in females (12.3%). Infection was age-dependent only in females. Prevalence of very large tattoos was also higher in males (28.6%) than in females (11.1%). These data suggest that male T. truncatus are more vulnerable to TSD than females, possibly because of differences in immune response and susceptibility to captivity-related stress.     

Beauveria bassiana affects immature stage development of Prostephanus truncatus (Coleoptera: bostrichidae) in stored maize

Recent research in Ghana has demonstrated the effectiveness of an isolate of B. bassiana, sensu lato (IMI 389521) from the U.K. against the larger grain borer Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), a major pest of stored maize. To determine whether this isolate is effective on immature stages of P. truncatus, a laboratory study of the response of immature stages (egg, larvae and pupae) of P. truncatus in maize grains to two concentrations (1?×?10⁹ and 3.16?×?10⁹?cfu/kg maize) of B. bassiana, IMI 389521 formulated with Entostat? and kaolinite was undertaken. Adult emergence, per cent survival of adults that emerged and the number of larvae in each immature stage were assessed after 45 days. Apart from the egg experiment, higher numbers of adults emerged in grains containing larvae and pupae treated with B. bassiana product compared to the untreated maize control. This notwithstanding, survival of emerged adults of P. truncatus was greatly reduced in B. bassiana treatments (<10%) compared with 75–95% in the controls. Surface treatment with B. bassiana on pre-infested maize showed a significant effect on the developmental biology of P. truncatus in Ghana.     

Defining bottlenose dolphin (Tursiops truncatus) stocks based on environmental,physical, and behavioral characteristics

The population structure of bottlenose dolphins, Tursiops truncatus, along the U.S. Atlantic coast has recently been redefined from one homogenous population into five coastal stocks. Local studies indicate even finer structure, primarily based on isolation of dolphins inhabiting estuaries. We identified population structuring of non‐estuarine coastal bottlenose dolphins during a study in New Jersey, the northern range along the Atlantic Coast. Using photo‐identification and distribution survey results, an analysis identified two major clusters of individuals significantly separated by five variables (distance from shoreline, group size, occurrence of the barnacle Xenobalanus globicipitis, avoidance behavior, and individual coloration). Sightings assigned to cluster 1 occurred in nearshore shallow waters (0–1.9 km, x?= 3.5 m), and those assigned to cluster 2 occurred further offshore in deeper waters (1.9–6 km, x?= 9.5 m). Only eight of 194 individuals (4%) were identified in both regions. Collectively, this suggests an occurrence of two stocks that are spatially, physically, and behaviorally distinguishable over a small distance. These results indicate that complexity in Tursiops population structure is not limited to latitudinal gradients or barriers created by estuarine habitats, but also by partitioning of habitat as a function of distance from shore and depth over small distances.