Sperm Storage in a Family-Living Lizard, the Tree Skink (Egernia striolata)

The ability to produce viable offspring without recently mating, either through sperm storage or parthenogenesis, can provide fitness advantages under a suite of challenging ecological scenarios. Using genetic analysis, we demonstrate that three wild-caught female Tree Skinks (Egernia striolata) reproduced in captivity with no access to males for over a year, and that this is best explained by sperm storage. To the best of our knowledge, this is the first time female sperm storage has been documented in any monogamous family-living reptile, including social Australian egerniine skinks (from the subfamily Egerniinae). Furthermore, by using paternal reconstruction of genotypes we show that captive-born offspring produced by the same females in the preceding year, presumably without sperm storage, were sired by different males. We qualitatively compared aspects of these females’ mates and offspring between years. The parents of each litter were unrelated, but paternal and offspring genotypes from litters resulting from stored sperm were more heterozygous than those inferred to be from recent matings. Family-living egerniine skinks generally have low rates of multiple paternity, yet our study suggests that female sperm storage, potentially from outside social partners, offers the real possibility of benefits. Possible benefits include increasing genetic compatibility of mates and avoiding inbreeding depression via cryptic female choice. Sperm storage in Tree Skinks, a family-living lizard with a monogamous mating system, suggests that females may bet-hedge through extra-pair copulation with more heterozygous males, reinforcing the idea that females could have more control on reproductive outcomes than previously thought.

Recapitulating Zika Virus Infection in Vagina of Tree Shrew (Tupaia belangeri)

Sexual transmission of Zika Virus (ZIKV) elevates the risk of its dissemination in the female reproductive tract and causes a serious threat to the fetus. However, the available animal models are not appropriate to investigate sexual transmission, dynamics of ZIKV infection, replication, and shedding. The use of tree shrew as a small animal model of ZIKV vaginal infection was assessed in this study. A total of 23 sexually mature female tree shrews were infected with ZIKV GZ01 via the intravaginal route. There was no significant difference in change of body weight, and the temperature between ZIKV infected and control animals. Viral RNA loads were detected in blood, saliva, urine, and vaginal douching. ZIKV RNA was readily detected in vaginal lavage of 22 animals (95.65%, 22/23) at 1 dpi, and viral load ranged from 104.46 to 107.35 copies/ml, and the peak of viral load appeared at 1 dpi. The expression of key inflammatory genes, such as IL6, 8, CCL5, TNF-a, and CXCL9, was increased in the spleen of ZIKV infected animals. In the current study, female tree shrews have been successfully infected with ZIKV through the vaginal route for the first time. Interestingly, at first, ZIKV replicates at the local site of infection and then spreads throughout the host body to develop a robust systemic infection and mounted a protective immune response. This small animal model is not only valuable for exploring ZIKV sexual transmission and may also help to explain the cause of debilitating manifestations of the fetus in vivo.

Structure, Reproductive Biology, and Regeneration Status of Podocarpus falcatus (Thunb.) R. B. ex Mirb. in Bale Mountains, Southern Ethiopia

This study was carried out in the Dodola forest, Southern Ethiopia, to investigate the structure, reproductive biology, and regeneration status of Podocarpus falcatus. Based on their disturbance status, two blocks each having an area of 16 ha (400 m × 400 m) were laid in the forest to collect vegetation data. 16 plots (100 m × 100 m) and 256 subplots (25 m × 25 m) were established in each block. The population status of Podocarpus falcatus (dbh ≥ 5 cm) was assessed in the 256 subplots. The regeneration status of Podocarpus falcatus was also assessed around 40 randomly selected female trees isolated at least 10 m from any other female tree in each block. A total of 1363 Podocarpus falcatus individuals were recorded, with an average distribution of 43 individuals ha−1 and a higher proportion of small-sized individuals. The population structures of Podocarpus falcatus in the two blocks were a typical inverted J-shape pattern, indicating good regeneration and recruitment status of the study species. Podocarpus falcatus had a good regeneration status in Dodola forest and also larger quantities of its seedlings were recorded under canopy shades suggesting that the species is shade tolerant. The density of seedlings and saplings was small within 4 m radius from the seed source (female trees) compared to that observed greater than 4 m distance. Thus, poor regeneration is observed within a 4 m radius around the female trees compared to distances greater than 4 m. Therefore, the local community and other responsible stakeholders should work together to stop and/or reduce the selective cutting of this ecologically and economically important tree species in the forest.

Does experimentally altered plumage brightness influence extra-pair mating success in female Tree Swallows (Tachycineta bicolor)?

Recent empirical evidence suggests that ornamental traits displayed by female birds may reflect aspects of their quality, and function during competitive interactions and (or) social mate attraction; however, less is known about how such traits influence extra-pair paternity. In Tree Swallows (Tachycineta bicolor (Vieillot, 1808)), plumage brightness of females signals their quality and may be related to extra-pair paternity if it enables them to invade the territories of other females to seek extra-pair copulations and (or) if potential extra-pair mates perceive their plumage brightness as attractive. Therefore, to examine whether the plumage brightness displayed by females influence rates of extra-pair paternity and the number of sires per brood, we experimentally enhanced and reduced the plumage brightness of females relative to controls. Our results showed that plumage brightness treatment of the female did not influence the number of extra-pair offspring in nests or the likelihood of a brood containing extra-pair offspring. Additionally, the number of extra-pair males siring offspring within the broods of females did not differ by plumage brightness treatment. Although extra-pair paternity has been shown to be beneficial for female Tree Swallows, our results suggest that plumage brightness of females does not influence their ability to engage in extra-pair mating.

Overcoming the pollination barrier through artificial pollination in the Wild Nutmeg Knema attenuata (Myristicaceae), an endemic tree of the Western Ghats, India

The barrier to pollination and pollinator assemblage were investigated in Knema attenuata, a dioecious tree species endemic to the Western Ghats of India. It occupies an intermediate canopy stratum of the low and mid-elevation wet evergreen forests. In order to observe floral display, insect foraging and fruit development, four populations of K. attenuata were selected. The population diagram of each population was constructed by marking one female tree as the centre and male trees available at different radii from the female tree. Direct observations and swap net trapping were used to sample insects in the canopy during the flowering season of 2016 and 2017. Knema attenuata exhibited generalised pollination through diverse insects: thysanopterans (thrips), coleopterans (beetles), halictid bees, and dipterans (syrphid and phorid flies), where thrips played the major role. On analysing the floral display, it was found that the male flowers provided no rewards and thus attracted less pollinators than the female flowers. Among the four populations studied, three showed more than 70% fruit setting and the rate of abscission in flowers and young fruits were negligible. One population was without fruit setting and trials on artificial pollination resulted in fruit setting. A very low frequency of seed germination was observed in natural conditions which was enhanced by a seed germinator.