Indo-Pacific lionfishes, Pterois volitans (Linnaeus, 1758) and Pterois miles (Bennett, 1828), native to the Pacific and Indian Oceans, respectively, were first observed in the western Atlantic off Florida in 1985. They have since spread and are established throughout the broader Caribbean region. Despite potentially devastating ecological and economic effects, information on key life history characteristics for lionfish in the invaded range is sparse. Objectives of this study were to quantify 1) periodicity in gonad development and spawning, 2) spawning frequency, 3) batch fecundity and 4) female size at maturity for fish from Little Cayman. Calculation of gonadosomatic indices, histological and macroscopic staging of gonads, and counts of hydrated oocytes were applied to determine reproductive characteristics. Higher gonadosomatic indices were recorded for females during periods of stable warm or cool water temperatures indicating that extreme temperatures did not constrain reproduction. Histological and macroscopic staging suggested that male and female lionfish were capable of reproducing year-round. However, higher gonadosomatic indices in females, as expected before spawning, were most pronounced in March/April and August. Based on the proportion of females containing hydrated oocytes, mature lionfish had the potential to spawn every 2–3 d. Ovaries of mature females contained 1800–41945 oocytes that were hydrated in preparation for spawning, with greater numbers of oocytes in larger females. Female lionfish matured at 189–190 mm total length. Parameters estimated in this study can improve outputs from population dynamic models, which will help resource managers design removals and other efforts to control invasive lionfish.
The rise in temperatures as a result of climate change will have adverse effects on various crops. Mungbean ( L.) is grown as a summer-season crop in many parts of the world. The optimum temperature for growth of mungbean is 28–30 °C; increase in temperatures above these limits, especially during reproductive growth, are expected to inhibit its potential performance. Hence a study was conducted to evaluate the effects of high temperatures (>40/25 °C; day/night) during reproductive growth on performance of mungbean and to probe the mechanisms associated with reproductive failures. Here, we tested two extra-short duration (60 days) mungbean genotypes for their response to heat stress under outdoor conditions as well as controlled environment (CE). Two mungbean cultivars (SML 832 and 668) were grown in pots at two sowing dates: (1) the normal sowing time (NS) on 30th March so that day/night temperatures during the reproductive stage were below 40/25 °C. The plants were fully irrigated during both the sowing situations to avoid any effect of drought stress. While phenology, duration of flowering, podding was not affected, there was a significant reduction in biomass (16–19%), pod set, number of filled pods (32–38%), seed number (43–47%) and seed yield (35–40%) on per plant basis due to heat stress in LS plants. This was associated with reduction in reproductive function such as pollen viability, pollen germination, pollen tube growth, pollen load and stigma receptivity in heat-stressed (HS) plants. At flowering and podding stage, stomatal conductance and photosynthetic efficiency and chlorophyll concentration were inhibited in leaves of both the genotypes under heat stress. A significant decrease was noticed in sucrose concentration in leaves and anthers along with reduction in activities of sucrose synthesising enzymes (sucrose synthase, sucrose phosphate synthase) and hydrolysing enzymes (acid invertase), which possibly was a vital reason affecting the reproductive function and yield traits. CE studies also revealed that temperatures more than 35/25 °C, especially 43/30 °C, 45/32 °C (day/night) were highly detrimental for pod set, reproductive function and yield traits for mungbean.
Collecting seed from natural plant populations is a key tool for conservation, ecological restoration, assisted migration, studying plant mating systems, and crop breeding. Many collections rely on simple, broadly-applied rules-of-thumb for minimum sample sizes, regardless of species’ natural history, and are likely inadequate for obtaining sufficient genetic representation. There is a current paucity of information about how various logistical and biological factors influence seed sampling outcomes. Here we use simulated and empirical data to, for the first time, quantitatively evaluate the degree to which collection effectiveness is influenced by spatial arrangement, sampling intensity, and species’ reproductive biology. We clearly and quantitatively demonstrate that collections with spatially limited or biased sampling arrangements, or collections from species with high selfing or low dispersal, will need substantially more samples than are commonly recommended, or else will fail to reach the targeted genetic diversity. We also show that the marginal gain from sampling additional maternal plants will nearly always exceed that of additional seeds. Lastly we show that random sampling outperforms “easy access” and “transect” sampling by 70% and 30%, respectively. Overall, we conclude that collection guidelines tailored to particular taxa will help facilitate optimal sampling design.
The reproductive biology of the European badger (Meles meles) is of wide interest because it is one of the few mammal species that show delayed implantation and one of only five which are suggested to show superfetation as a reproductive strategy. This study aimed to describe the reproductive biology of female Irish badgers with a view to increasing our understanding of the process of delayed implantation and superfetation. We carried out a detailed histological examination of the reproductive tract of 264 female badgers taken from sites across 20 of the 26 counties in the Republic of Ireland. The key results show evidence of multiple blastocysts at different stages of development present simultaneously in the same female, supporting the view that superfetation is relatively common in this population of badgers. In addition we present strong evidence that the breeding rate in Irish badgers is limited by failure to conceive, rather than failure at any other stages of the breeding cycle. We show few effects of age on breeding success, suggesting no breeding suppression by adult females in this population. The study sheds new light on this unusual breeding strategy of delayed implantation and superfetation, and highlights a number of significant differences between the reproductive biology of female Irish badgers and those of Great Britain and Swedish populations.
Hybridization is an important evolutionary force in plants, but the mechanisms underlying it have not been well studied for many groups. In particular, the drivers of non-random patterns of interspecific gene flow (asymmetrical hybridization) remain poorly understood, especially in the seed-free vascular plants. Here, we examine patterns of asymmetrical hybridization in two widespread fern hybrids from eastern North America and study the role of gametophyte ecology in the determination of hybridization bias. We characterized the maternal parentage of > 140 hybrid sporophytes by sequencing a . 350-bp region of chloroplast DNA (cpDNA). To identify factors contributing to patterns of asymmetrical hybridization, we cultured gametophytes of the parental species and evaluated critical aspects of their reproductive biology. We found that asymmetrical hybridization was prevalent across the populations of both hybrids. Reproductive traits varied across species and suggest that selfing potential, antheridiogen responsiveness, sperm dispersal capacity and gamete size all contribute to the mediation of the direction of hybridization in this group. Our findings suggest that asymmetrical hybridization in ferns is driven by an array of reproductive traits. This study helps to sharpen and define a mechanistic understanding of patterns of hybridization in this group and demonstrates the importance of considering gametophyte biology when studying evolutionary processes in ferns.
Most skates are adapted to shelf and slope environments experiencing less seasonal variation than coastal ecosystems. Here, we analyze the reproductive ecology of Sympterygia acuta. We hypothesize that, like its congener Sympterygia bonapartii, S. acuta has a seasonal reproductive cycle. To test this hypothesis, we examined multiple lines of evidence: (1) time of appearance of females carrying egg cases and wild neonates; (2) seasonal variation in gonadosomatic index and follicle diameter, as indicators of reproductive activity; and (3) egg-laying season, incubation time, and fecundity in captive individuals. A total of 351 specimens were examined. Size at 50 % maturity was 475 and 478 mm total length for males and females, respectively. A marked seasonal reproductive cycle was observed. Both gonadosomatic index and follicle diameter of wild adult females increased from winter to spring and reached their lowest value during summer. Fecundity was, on average, 52 eggs per female per laying season. Egg laying of captive females peaked between August and December; eggs hatched after 119-131 days. This schedule predicts the appearance of neonates in the wild by January through April. Accordingly, wild neonates and young-of-theyear were observed between January and May. Unlike most other skates, southwest Atlantic Sympterygia species are adapted to life in shallow, coastal waters, matching the seasonality of the coastal environment with egg-laying activity in spring and hatching in summer. These shallow coastal waters, which are important in the life cycle of Sympterygia spp., are threatened by human impacts.