Interspecific variations in external and internal egg quality among various captive avian species from Punjab, Pakistan

Present study was planned to determine variations in external and internal quality egg parameters of different avian species including ostrich Struthio camelus, ducks Anas platyrhynchos, chicken Gallus gallus, turkeys Meleagris gallopavo and grey francolin Francolinus pondicerinus. All the birds were kept under similar rearing conditions. A total of 150 eggs were collected for each species to record external features of these eggs. Statistically significant (p<0.05) variations were recorded in egg weight, egg length and egg width between ostrich, ducks, chicken, turkey and quail eggs. Significantly (p<0.05) higher egg weight, egg length and egg width was observed for ostrich eggs while the same was lowest for grey francolin eggs. Similarly, significantly (p<0.05) greater shape index and egg volume values were observed for ostrich eggs while lowest shape index values were recorded for turkey eggs and egg volume was lowest for grey francolin. Significantly, higher (p<0.05) values of egg density were noted for eggs of the quail and the same were lowest for ostrich eggs. Non-significant variations in egg density values were observed between eggs of the ducks, chicken, turkey and grey francolin. It has been concluded that the positive correlations between the internal and external egg quality traits indicated that the traits can be improved through selection.

Egg size variation in a long-lived polyandrous shorebird in the context of senescence and breeding phenology

Anisogamy is a central component of sex role evolution, however, the effect of female-female mating competition on egg size variation in polyandrous species is unclear. Moreover, egg size may also be shaped by age-dependent trade-offs between reproductive investments and somatic maintenance that are responsible for senescence. Here we investigate how mating behaviour and senescence are associated with egg size variation in female snowy plovers (Charadrius nivosus). Snowy plovers are long-lived shorebirds (longevity record: 20 years) that often produce several nests each year, with females either sequentially changing partners between breeding attempts or remaining monogamous between attempts. We examined how age, seasonality, body size, and mating behaviour relate to within- and between-female variation in egg volume using repeated measures collected over a 15-year period. We found no evidence of reproductive senescence in egg volume in snowy plover females. Rather, egg volume, polyandry, and re-nesting were strongly linked to breeding phenology: early breeding females had a higher likelihood of being polyandrous or replacing failed clutches, yet these individuals laid smaller eggs likely due to physiological limitations associated with the early season. Older individuals and local recruits secured the earliest breeding opportunities in the season suggesting that prior experience could give an edge in the female-female competition for mates. Larger females laid the largest eggs, as expected, but there was no relationship between body size and lay date - implying that size may not provide an advantage in female-female competition. Our findings highlight the existence of several direct and indirect constraints on female reproductive investment that likely shape individual variation in lifetime reproductive success. Future research investigating reproductive senescence of wild populations should consider mating system dynamics when examining variation in reproductive investment.

The morphometric analysis of Eurasian coot eggs (Fulica atra) under the local conditions from Câmpenești, North-Western Romania

The aim of the present paper was to analyze the measurements of the Eurasian Coot (Fulica atra) eggs in order to evaluate if the local conditions, presented here, differ in some way from older data found in references dating to 1955 in Romania. The data were collected from the Eurasian Coot nests identified (N=8) at Câmpenești fishponds, located in North-Western Romania, in May 2018. The clutch size was 7.5 ±1.6, ranging from 5 to 10 eggs. The mean egg length was 50.81 mm, and the mean egg breadth was 34.5 mm with higher variability in case of the first measurement. The mean egg volume was 31.3 cm3 which is much smaller than reported in the Romanian references (36.13 cm3). Regarding intra-clutch variance, we found that some clutches manifest a higher length, breadth and volume variance than others which can be a result of the intraspecific nest parasitism or environmental variances. The results brought some extensions of egg length and egg breadth limits and also may reflect a decrease in egg size over time.

Reproductive plasticity of Hawaiian Montipora corals following thermal stress

Ocean warming, fueled by climate change, is the primary cause of coral bleaching events which are predicted to increase in frequency. Bleaching is generally damaging to coral reproduction, can be exacerbated by concomitant stressors like ultraviolet radiation (UVR), and can have lasting impacts to successful reproduction and potential adaptation. We compared morphological and physiological reproductive metrics (e.g., sperm motility, mitochondrial membrane integrity, egg volume, gametes per bundle, and fertilization and settlement success) of two Hawaiian Montipora corals after consecutive bleaching events in 2014 and 2015. Between the species, sperm motility and mitochondrial membrane potential had the most disparate results. Percent sperm motility in M. capitata, which declined to ~ 40% during bleaching from a normal range of 70–90%, was still less than 50% motile in 2017 and 2018 and had not fully recovered in 2019 (63% motile). By contrast, percent sperm motility in Montipora spp. was 86% and 74% in 2018 and 2019, respectively. This reduction in motility was correlated with damage to mitochondria in M. capitata but not Montipora spp. A major difference between these species is the physiological foundation of their UVR protection, and we hypothesize that UVR protective mechanisms inherent in Montipora spp. mitigate this reproductive damage.

Long-term stability in the volume of Atlantic Puffin (Fratercula arctica) eggs in the western North Atlantic

In the eastern North Atlantic, declines in the volume of Atlantic Puffin (Fratercula arctica Linnaeus, 1758) eggs have been associated with shifts in the marine ecosystem, such as changes in the abundance of forage fishes and increasing sea-surface temperatures. In the western North Atlantic, where similar shifts in oceanographic conditions and changes in the abundance of forage fishes have presumably occurred, trends in the volume of Atlantic Puffin eggs remain unknown. In this study, we investigate Atlantic Puffin egg volume in the western North Atlantic. We compiled 140 years (1877–2016) of egg volume measurements (n = 1,805) and used general additive mixed-effects models to investigate temporal trends and regional variation. Our findings indicate that Atlantic Puffin egg volume differs regionally but has remained unchanged temporally in the western North Atlantic since at least the 1980s.

Breeding biology of a relictual Maghreb Magpie (Pica mauritanica) population in Tunisia

Background The Maghreb Magpie (Pica mauritanica) is an endemic North African species. Available knowledge on this species is limited to historic descriptive data with no ecological information provided. Populations continue to dramatically decline in Tunisia, where only one relic population survives. Investigating the breeding biology of this species is essential for conservation purposes. The purpose of this study was to increase our understanding of the Tunisian relic population and provide detailed data on breeding biology over two breeding seasons (2017 and 2018). Methods This study occurred on a private farm of 650 ha, located 10 km from Dhorbania village at Kairouan Governorate, in central Tunisia. Active nests were monitored weekly during egg laying period and twice a week during hatching period. The Ivlev’s electivity index was used to assess whether the frequency of use of nesting trees and bushes matched their availability in the study area. We recorded nest measurements and positions, and compared them using Wilcoxon signed-rank test. Variations of breeding parameters as number of eggs laid, hatchlings, and fledglings over years were performed using Mann–Whitney U-test and χ2 tests. We used a Generalized Linear Mixed Model (GLMM) to investigate how egg volume varied with clutch size and laying date. Results We investigated clutch size, egg size, hatching and fledging success, and evaluated how these parameters varied according to laying date and nest characteristics. Clutch size averaged 5.00 ± 0.19 but was significantly greater in 2017. Hatching success was 2.78 ± 0.34 eggs hatched per nest and fledging success reached 1.69 ± 0.30 young/nest. Causes of nest failure included the depredation of nestlings by shrikes, cobras and rats (e.g. Lanius meridionalis, Naja haje and Rattus rattus), death of parents by the Black-shouldered Kite (Elanus caeruleus) and nest parasitism by the Great Spotted Cuckoo (Clamator glandarius). Clutch size, brood size and fledgling success were unaffected by laying date, nest volume and nest elevation. Egg volume decreased with laying date but was unaffected by clutch. Conclusion Our study provides the first and only detailed data on reproductive parameters of the Maghreb Magpie in its entire geographic range (North Africa). Information gleaned from this study provides valuable information for monitoring and long-term conservation plans of the endangered Tunisian Magpie population. Additionally, our data provide an avenue of large-scale comparative studies of the reproductive ecology of the magpie complex.

Effects of mating on reproductive performance of Coccophagus japonicus Compere (Hymenoptera: Aphelinidae)

Coccophagus japonicus Compere, an endoparasitoid of Parasaissetia nigra Nietner, has great potential for biological control. To assess the influence of mating on the reproductive performance of this parasitoid, we examined the effects of mating on ovarian development, female longevity and number of eggs laid. The results showed that the egg volume in the ovary of C. japonicus first increased and then decreased with increases in the age of female adults. The peak egg volume in the ovary of mated females occurred 2 days earlier than that of virgin females. Within the female age range of 0–15 days, the numbers of eggs at stages I, II, and III first increased and then decreased with increases in the age of female C. japonicus, whereas the number of eggs at stage IV increased. The duration of the coexistence of females and males significantly influenced the length and width of the female ovaries, and the longest ovary tube and the highest number of eggs were obtained with a coexistence duration of 0 days. C. japonicus female longevity decreased with increases in the number of matings, and the number of eggs laid by females within 15 days decreased with increasing delays in mating. In conclusion, mating can shorten the longevity of C. japonicus females, and selecting newly emerged virgin females for mating can significantly improve the number of eggs laid and the breeding efficiency of the parasitoid.

Incubation Onset Influences Maternal Investment in Eggs and Egg and Nestling Survival in an Altricial Bird

Many birds initiate incubation before clutch completion which results in asymmetric survival of eggs and nestlings within the clutch. When parents start incubating before clutch completion, low survival is expected of the nestlings hatched from eggs laid after the onset of incubation due to hatching asynchrony. Conversely, eggs laid before the onset of incubation may have a lower survival because of extrinsic factors (e.g. ambient temperature and microbial infection). Many studies investigating the allocation of parental investment have hypothesized two different strategies wherein parents allocate investment that favors eggs/nestlings with high survival prospects or compensates for the disadvantages of eggs/nestlings with low survival prospects. Although birds could take different strategies based on incubation onset within the same breeding attempt, this idea has never been tested. We conducted an observational study to investigate the effects of incubation onset on the survival of eggs laid before and after incubation onset and parental egg allocation in the altricial wryneck Jynx torquilla. We found that survival decreased in the eggs laid earlier or later than the day of incubation onset within the clutch. Because egg volume increased with laying sequence, egg volume and the survival of eggs laid before incubation onset were positively associated, whereas egg volume and the survival of eggs laid after incubation onset were negatively associated. Furthermore, late-hatching nestlings grew to similar weights to early-hatching nestlings. These suggest that females proportionately invested in egg size before incubation onset, but that investment in egg size after incubation onset was compensatory. Our observational study proposes a possibility that female wrynecks adopt two different investment strategies before and after incubation onset during a breeding attempt.

Effects of Probiotic Fermented Kitchen Waste on the Growth and Propagation of Rotifer Brachionus calyciflorus

Kitchen waste containing a large number of nutrients such as carbohydrates, proteins, lipids, and minerals can be used as fermentation substrates for producing probiotics, and then can be taken as microbial feed to cultivate rotifer. This approach not only emphasizes resource utilization of kitchen waste but also improves the growth and propagation of rotifer. In this study, kitchen wastewater and solid waste were used as fermentation substrates, respectively, while yeast, lactic acid bacteria, compound bacteria (yeast + lactic acid bacteria), and effective microorganisms (EM) bacteria were inoculated to harvest the microbial feed for the cultivation of rotifer. The population density, eggholding rate, body length, and the egg volume of rotifer were determined. These results indicate that the growth and propagation of rotifer were effectively improved by using kitchen wastewater or solid waste as fermentation substrates. When compared with the direct usage of kitchen waste for rotifer cultivation, the effect of kitchen waste fermented by probiotics on rotifer was more obvious, such as in the population density, egg-holding rate, body length, and egg volume, in the following sequence EM bacterial group > yeast group > compound bacterial group > lactic acid bacterial group ^ control group. Hence, EM bacteria can be considered as the best one for kitchen waste fermentation to prepare microbial feed for rotifer. It is thus feasible to use probiotic fermented kitchen waste to cultivate rotifer.