BMC Zoology最新文献

Budorcas taxicolor bedfordi is a rare animal uniquely distributed in the Qinling Mountains (China). Human disturbance and habitat fragmentation have directly affected the survival of B. t. bedfordi. It is urgent to clarify the genetic diversity and genetic structure of the B. t. bedfordi population and implement effective conservation measures. In this study, 20 new polymorphic microsatellite loci were isolated by Illumina sequencing. The genetic diversity and population structure of 124 B. t. bedfordi individuals from three populations (Niubeliang population, Zhouzhi population, and Foping population) were analysed according to these 20 microsatellite loci. Our results indicated that B. t. bedfordi had a low level of genetic variability and that there was inbreeding in the three populations. The population genetic structure analyses showed that the Niubeliang population had a trend of differentiation from other populations. National roads can affect population dispersal, while ecological corridors can promote population gene exchange. None of the three B. t. bedfordi populations experienced bottleneck effects. For conservation management plans, the Zhouzhi population and Foping population should be considered one management unit, and the Niubeliang population should be considered another management unit. We suggest building an ecological corridor to keep the habitat connected and formulating tourism management measures to reduce the influence of human disturbance on B. t. bedfordi.

Background: Phasmatodea are well known for their ability to disguise themselves by mimicking twigs, leaves, or bark, and are therefore commonly referred to as stick and leaf insects. In addition to this and other defensive strategies, many phasmatodean species use paired prothoracic repellent glands to release defensive chemicals when disturbed by predators or parasites. These glands are considered as an autapomorphic trait of the Phasmatodea. However, detailed knowledge of the gland anatomy and chemical compounds is scarce and only a few species were studied until now. We investigated the repellent glands for a global sampling of stick and leaf insects that represents all major phasmatodean lineages morphologically via µCT scans and analyzed the anatomical traits in a phylogenetic context.

Results: All twelve investigated species possess prothoracic repellent glands that we classify into four distinct gland types. 1: lobe-like glands, 2: sac-like glands without ejaculatory duct, 3: sac-like glands with ejaculatory duct and 4: tube-like glands. Lobe-like glands are exclusively present in Timema, sac-like glands without ejaculatory duct are only found in Orthomeria, whereas the other two types are distributed across all other taxa (= Neophasmatodea). The relative size differences of these glands vary significantly between species, with some glands not exceeding in length the anterior quarter of the prothorax, and other glands extending to the end of the metathorax.

Conclusions: We could not detect any strong correlation between aposematic or cryptic coloration of the examined phasmatodeans and gland type or size. We hypothesize that a comparatively small gland was present in the last common ancestor of Phasmatodea and Euphasmatodea, and that the gland volume increased independently in subordinate lineages of the Occidophasmata and Oriophasmata. Alternatively, the stem species of Neophasmatodea already developed large glands that were reduced in size several times independently. In any case, our results indicate a convergent evolution of the gland types, which was probably closely linked to properties of the chemical components and different predator selection pressures. Our study is the first showing the great anatomical variability of repellent glands in stick and leaf insects.

Background: Various anthropogenic activities continue to threaten the fish biodiversity of the East African water bodies such as the Victoria Nile. Although the Victoria Nile is a significant source of livelihood for human populations, the biology and ecology of Nile tilapia in this ecosystem remain understudied with little or no information on the morphology of the fish given varying and immense anthropogenic activities. Here, we use geometric morphometrics to examine the morphology/shape variations of Nile tilapia populations in Victoria Nile to gain insights into their current ecological state.

Results: Our results indicate unexpectedly smaller Nile tilapia body weights in Victoria Nile than in L. Victoria. Despite this, nearly all the populations displayed a relative condition factor (Kn) of greater ≥1 suggesting a healthy stock. However, two populations, LMF and VN_Bukeeka demonstrated Kn values of less than one (< 1). We also report that some Upper and Lower Victoria Nile populations display morphological similarities. Apart from L. Albert, Nile tilapia populations from Lakes Victoria and Kyoga are morphologically divergent from the riverine ones. We note that Nile tilapia from Nalubale Dam Reservoir is morphologically distinct from the close neighbouring Victoria Nile populations which are likely allied to the influence of the Nalubale Hydroelectric power dam as a barrier.

Conclusion: Nile tilapia's morphological variation appears to be influenced by various anthropogenic disturbances notably, overfishing, hydroelectric power dams, and fish translocational history in Uganda. Management should enforce regulatory frameworks to avert human-mediated activities as these are likely to compromise the sustainability of the fisheries. Further studies are required to follow these populations with molecular genetics and environmental data to gain a deeper understanding of the fish species for informed sustainable management and conservation options.

Background: Livestock depredation by the black-backed jackal (Canis mesomelas) occurs widely across Africa. The study on human-jackal conflict is important for conservation efforts in Ethiopia. The aim of this study was to investigate the diet of black-backed jackals, to understand their predation effects on domestic livestock and perceptions of farmers' in the Konasa-Pulasa Community Conserved Forest, Omo Valley of Ethiopia. The study was conducted using scat analysis, questionnaire survey and Focus Group Discussion methods. Livestock depredation and the economic impact of farmers were assessed among 290 randomly selected households. A total of 90 scat samples were collected and analyzed during the dry and wet seasons to identify the diet of jackals.

Results: A total of 624 domestic animals have been lost in the last 5 years (2016-2020). The estimated economic cost of domestic animals lost due to predation by jackals was US $18,180.0 in the last five years, and US $12.5 per year per household. The major diet composition of jackals was of domestic animal origin (45.5%), followed by wild animals (30.8%) in both the dry and wet seasons. However, more prey diversity was recorded during the wet season. The respondents revealed that the causes of black-backed jackal conflict in the study area were higher due to increasing jackal population size (40%). The major traditional mitigation method was guarding (42%). Most of the respondents (48.2%) had negative perceptions towards the conservation of black-backed jackals.

Conclusion: Livestock depredations by black-backed jackals were the major issue of conflict in the study area. Scat analysis showed that large percentage of domestic animal species remain in the scat of jackals. Livestock losses caused by jackals represent an economic concern for livestock owners in the area. Local people close to the forest boundary were highly vulnerable to domestic animal loss due to predation by jackals. Therefore, improved livestock husbandry methods will be implemented by the local people for effective jackal conservation in Konasa-Pulasa Community Conserved Forest. Understanding the ecological and social dimensions of conflict situations in the area may have important ecological and management implications for the country.

Nowadays rewilding has received an increasing focus as a sustainable conservation tool for restoring damaged or disturbed habitats. Many types of rewilding initiatives have been implemented all over the globe with the goal of reinstalling the extinct or lost fauna as well as restoring ecological relationships and natural processes. The effectiveness of rewilding initiatives depends on a comprehensive understanding of the ecological functions, habitat needs, social behaviour, and interrelation among various animal species. This Collection invites contributions that portray different aspects and the importance of rewilding.

The acute toxicity and sublethal effects of ammonia and nitrite on the air-beathing Siamese fighting fish, betta (Betta splendens) was studied for 96 h. The LC50 (50% Lethal Concentration) for 96 h for adult bettas to ammonia-N and nitrite-N was 123.4 mM (1.7 g/L, 95% confidence limits: 114.7-130.0 mM) and 24.6 mM (343.6 mg/L, 95% confidence limits: 22.7-26.4 mM) respectively. Exposure to 90 mM ammonia did not affect ammonia and urea excretion rates in bettas. There was no significant difference in values between control and ammonia-loaded (90 mM ammonia) individuals in either brain or liver activities of glutamine synthase, while plasma ammonia levels slightly increased. It appears unlikely that ammonia was converted to urea or amino acids for detoxification. Sublethal nitrite (24.6 mM nitrite) affected plasma nitrite, methemoglobin and hemoglobin. Plasma nitrite values remained much lower than ambient concentrations. Betta has a labyrinth organ and can breathe air. Bettas may temporarily reduce the entry of ammonia and nitrite into the body by increasing the rate of air respiration and reducing the contribution of the gill epithelium, which is highly permeable to these nitrogenous pollutants.