BMC Zoology最新文献

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.

Background: Land use intensification may affect diversity, abundance, and functional morphological traits (FMT) related to dispersal, food acquisition, digestion, and nesting in some insects, possibly impacting their ecological role. Most studies of termites on the effects of afforestation focus on diversity and abundance, but changes in FMT have yet to be studied.

Aim: To better understand the response mechanisms to land use intensification, we compared the FMT of the worker and soldier caste of Heterotermes tenuis among Pinus caribaea plantations of four different ages and gallery forests of the Colombian Orinoquía.

Methodology: We measured thirty-eight FMTs in the worker and soldier castes of H. tenuis from gallery forests and pine plantations. Then, we used a Community-Weighted Mean (CWM), a PERMANOVA, and a nonmetric multidimensional scaling (NMDS) to estimate the possible effect of land use type on the FMT of both castes. We selected the FMTs with the lowest intraspecific coefficient of variation (CV) from each caste to compare their size among the land use types and pine plantation ages.

Results: Land use type had a more significant impact on the FMT size of pine plantation workers than the age of the afforestation. FMT of the worker caste tends to be larger in gallery forests than in pine plantations, while the results were inconclusive for soldiers.

Conclusion: The results suggested a homogenization mainly of the feeding FMT of the worker caste of H. tenuis in pine plantations associated with the increase in the softwood food resource of P. caribaea.

Background: Species adjust to changes in temperature and the accompanying reduction in resource availability during the annual cycle by shifts in energy allocation. As it gets colder, the priority of energy allocation to maintenance increases and reproduction is reduced or abandoned.

Results: We studied whether and how young female guinea pigs (Cavia porcellus) adjust even under ad libitum food conditions growth, storage of fat reserves and reproduction when kept at 5 °C versus 15 °C, and how offspring born into these conditions compensate during development to independence. Reproducing females grew less in the cold. Their lower weight resulted largely from less fat storage whereas growth in fat free mass was about the same for both groups. The increased need for thermoregulation diminished fat storage most likely due to the development of more brown fat tissue. Reproductive activity did not differ between groups in terms of litter frequency, mass and size. However, females in 5 °C weaned pups later (around day 25) than females in 15 °C (around day 21). Later weaning did not make up for the higher energy expenditure of pups in cold conditions leading to slower growth and less fat storage. Female pups born into the cold matured later than those born in 15 °C. Investment in reproduction continued but allocation to individual pups declined.

Conclusions: In more thermally demanding conditions female guinea pigs - even under ad libitum food abundance - transfer the higher costs of maintenance and reproduction largely to offspring.

This study investigated the reproductive traits of the hermaphroditic four-finger threadfin, Eleutheronema tetradactylum, along the coasts of Thailand during January to December 2021. Fish samples were collected from Pattani Bay, Thailand to assess the sex ratio, gonadosomatic index (GSI), maturity stage and fecundity. Additional fish samples were also collected from other areas to evaluate the length and weight at first sex change (Ls₅₀ and Ws₅₀) and length at first maturity (Lm₅₀). The overall sex ratio for male and female was 1:0.69 with male being predominant throughout the year. Threadfin fish spawn the whole year round with peaks during moderate rainy and heavy rainy seasons. Histological examination confirmed its protandrous hermaphrodite posing multiple spawning habits. The average fecundity was 1.85 × 10⁵ ± 1.05 × 10⁵ eggs and positively related with standard length, body weight, gonad weight, and egg diameter (p < 0.05). The Ls₅₀ and Ws₅₀ were 27.58 cm and 419.39 g, and 29.71 cm and 457.28 g, for fish from Pattani Bay and Samut Prakan province, respectively. The Lm₅₀ of male from Pattani Bay and Samut Prakan province were 25.78 cm and 25.56 cm, respectively, which were larger than those from Satun and Nakhon Sri Thammarat provinces. The Lm₅₀ of females from Pattani Bay was smaller than that from Samut Prakan province. This study provided fundamental information on the reproductive characteristics of E. tetradactylum, which can be implemented to support management of natural fish stock and aquaculture development.

Background: In this study, the effect of heavy metals accumulation influence was evaluated on adult crayfish Procambarus clarkii (Decapoda, Astacidea) collected from three different Governmental locations (Kafr El-Shaikh, El-Menofya, and El-Gharbiya) of the Egyptian Delta. The activity of super oxidase dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) of gills, hepatopancreas, and muscle tissue were measured. SDS Polyacrylamide gel electrophoresis (SDS-PAGE) and West blotting technique were performed to detect MT Protein expression.

Results: The results revealed that Kafr El-Shaikh reflected the highest Superoxide dismutase (SOD), Catalase, and Glutathione S-transferase (GST) activity levels (97.2 u/100 mg, 28.5 u/100 mg, and 8.3 nmol mg (-1) protein min (-1) respectively. Superior protein polymorphism % (30%) remarked collected Freshwater crayfish P. clarkii from Kafr El-Shaikh location. Varied protein polymorphism % was shown between collected crayfish from El-Menofya, and El-Gharbiya locations (5.5 and 6.2 respectively) Increasing Metallothioneins intensity (15.4%) for collected Freshwater crayfish Procambarus clarkii from Kafr El-Shaikh Location.

Conclusion: Heavy metal stress influences antioxidant status and also induces increasing Metallothioneins intensity, especially samples that were collected from the Kafr El-Shaikh area.

Background: Paphia undulata, The Short-Necked Clam, is an edible marine bivalve that is consumed internationally and locally in Egypt. Overfishing and pollution have caused population declines in Egyptian fisheries during the last decade. Accurate reproductive biology knowledge is critical for designing long-term exploitation strategy for this resource. P. undulata spawning and gametogenic cycle research were carried out from January to December 2020 along Timsah Lake, Suez Canal, Egypt.

Results: These clams are functionally dioecious with a very low incidence of hermaphroditism. The sex ratio of the clam population was 1.0:1.07:0.04 for male, female and hermaphrodite respectively. The shell lengths of the collected clams were 4.64 ± 0.83 cm in males, 4.55 ± 0.9 cm in females and 4.19 ± 0.3 cm in hermaphrodite clams. The sizes at the onset of sexual maturity in both males and females were 2.1 cm and 2.5 cm respectively.

Conclusions: Reproductive studies revealed that this species has a prolonged spawning season that is not restricted to a specific period.

Background: Ecomorphological studies of lizards have increasingly employed comparison of claw morphology among species in relation to spatial niche use. Typically, such studies focus on digit IV of the autopodia, especially the pes. Uniformity of claw morphology among digits is more often implicitly assumed than tested.

Results: Using four species of Cyrtodactylus, comprising two generalist and two scansorial taxa that use different substrates, we examined whether claw morphology is uniform among digits and among species. We found that, within each species, ventral claw curvature is uniform across all digits whereas there are small but insignificant differences in ventral claw length and claw depth. The claws of the pes of each species are longer and deeper than those of the corresponding digits of the manus. The claw of digit I of each species is significantly shorter and shallower on both autopodia compared to those on digits IV and V (digit I, including its claw, is idiosyncratically variable among lizards in general).

Conclusions: We conclude that digit IV is an adequate representative of claw form in each species and exhibits variation among species, thereby serving as an exemplar for use in studies of potential discrimination between ecomorphological types in studies of Cyrtodactylus.

Background: Most aquatic biota's reproductive biology and life cycle are essential to the sustainable management and development of coastal ecosystems and aquaculture. The bivalve Paphia textile (Gmelin 1791), also known as Paratapes textilis, has an economic value in Indo-Pacific waters, including the Red Sea and the Suez Canal lakes, the Egyptian coasts. However, P. textile suffers from extensive fishing and exploitation.

Aim: The present work aims to study the Paphia textile's reproductive cycle on the Egyptian coasts of the Red Sea for the first time. It helps to manage and develop the coastal ecosystems and aquaculture.

Methodology: Samples were collected monthly from two saline lakes in the Suez Gulf from December 2019 to November 2020. As part of the comprehensive research study, sex ratio, condition index, sexuality, histological analysis of gonads, shell size, and gonad index were used to investigate the reproductive cycle.

Results: The results reveal a male-biased sex ratio, possibly due to anthropogenic stressors. The Paphia textile is dioecious. No hermaphrodite cases were observed in the studied specimens. The condition index in winter and spring indicates periods dominated by mature individuals. Five reproductive maturity stages were assigned for both P. textile males and females. Due to the simultaneous development of several developmental stages monthly throughout the sampling year, warm water may be responsible for non-sequential gametogenic cycles. As measured environmental parameters correlate with maturity stages, temperature, salinity, and chlorophyll a play important role in gonad growth. The size at first sexual maturity at which 50% of the Paphia textile population reached maturity ranged from 28.60 to 31.50 mm for females, and between 31.70 and 34.10 mm for males. As the gonad index increases during the ripe stages, this index decreases during the resting, spawning, and spent phases.

Conclusions: The findings suggest the most suitable temperature for aquaculture spawning is between 20 °C and 30 °C in subtropical waters. Fishing should generally be prohibited at sizes less than 28.60 mm for better management and sustainability of this valuable aquatic resource on the Egyptian coasts of the Red Sea.

Background: Under the family Tephritidae, Bactrocera zonata (Saunders) is a serious pest, attacking fruits and vegetables causing large quantitative and qualitative damages throughout the world. Fruit flies require proteinaceous food for sexual maturation and egg development. Therefore, food bait attractants are frequently utilized for fruit fly detection, monitoring, mass trapping, and control. Using a Y-shape olfactometer (behavioral tests), we selected the best synthetic proteinaceous food bait attractants to volatiles identified by fruit fly antennae. The responses of B. zonata adults, male and female, to some ammonium compounds (ammonium acetate (AA), trimethylamine (TMA), and putrescine) that were mixed with certain food attractants were evaluated under laboratory conditions. Using flies ranging in age from 5 to 30 days, possible mixtures were discovered that might be useful in developing fruit fly attractants for both males and females. So, four base baits were developed by mixing protein hydrolysate with jaggery, papaya powder, kachri powder, potassium hydroxide (KOH), and guava pulp. Finally, thirty-two (32) synthetic blends were developed when the above four base baits were mixed with synthetic attractants.

Results: The olfactometer bioassay indicated that protein hydrolysate and jaggery-based baits were effective in attracting both male and female flies throughout their adult lives when combined with AA + putrescine (Bait 6) and AA + TMA + putrescine (Bait 8). Similarly, protein hydrolysate + guava pulp-based baits combined with AA + putrescine (Bait 6) and AA + TMA + putrescine (Bait 8) was effective in attracting both male and female flies from 5 to 30 days of age. The pH of all 32 synthetic blends was measured and ranged from 4.77 to 11.35.

Conclusions: According to our observation, the variation in pH may be due to differences in chemical composition between the attractants and food constituents. The pH of protein bait attractants may be an important factor in the attraction efficiency of B. zonata males and females.