Extra-pair paternity in a species with frequent extra-pair courtship feedings, few extra-pair copulations, and male-biased parental care

Patterns of extra pair paternity (EPP) and intraspecific brood parasitism (IBP) were studied in a Whiskered Tern Chlidonias hybrida population characterized by female brood desertion, a high level of extra pair courtship feedings (10%) and a low level of extra pair copulation (EPC; 0.6%). In this study, we used a set of microsatellite loci to analyse parentage in 56 Whiskered Tern families from southern Poland. Depending on the method, we detected that 1.4%–3.6% of chicks were sired by an extra-pair male, and extra-pair chicks were present in 3.6%–8.9% of broods. IBP was observed in 8.9%–14.3% of broods, corresponding to 3.6%–6.4% of the chicks. The low rate of EPP is in agreement with the hypothesis that in species with high male parental investment, females should avoid EPC. The low level of IBP indicates that intraspecific egg dumping is not a common female strategy in Whiskered Tern, similar to many other colonial waterbird species.

Dose Optimization of Ovatide Hormone for Induced Breeding of Freshwater Gang Magur, Hemibagrus Menoda (Hamilton, 1822)

An experiment on induced breeding of gang magur, Hemibagrus menoda (Hamilton, 1822) using Ovatide hormone was carried out at in the Field Laboratory Complex of Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh. This study consists of three treatments each with three replications. The objective of the experiment was to find out the effective dose of Ovatide hormone for induced breeding. A total number of 54 brood fish were used for the experiment among which 36 were male and 18 were female. Brood fish were kept in the ratio of 2♂:1♀ for breeding purpose. Female brood fish were injected at the rate of 7, 5, 3 ml Ovatide/kg body weight while the males were injected with 3, 2.5 and 1.5 ml Ovatide/kg body weight respectively in T1, T2, and T3 at the same time. The brood fish were injected with single dose of Ovatide in all treatments. Ovulation rates were 0%, 100%, 63%; fertilization rates were 0%, 97%, and 90%, and hatching rates were 0%, 95% and 76% in treatments T1, T2, and T3 respectively. Fertilized eggs were incubated for 21-22 h in all the treatments. Higher ovulation rate (100 %), fertilization rate (97%), hatching rate (95%) and survival rate (85%) were found in treatment T2. Therefore, the optimum dose of Ovatide hormone for induced breeding of H. menoda is 2.5 and 5 ml Ovatide/kg body weight of male and female brood fish, respectively. Res. Agric., Livest. Fish.8(1): 171-179, April 2021

Split sex ratios and genetic relatedness in a primitively eusocial sweat bee

In eusocial Hymenoptera, queens and their helper offspring should favour different sex investment ratios. Queens should prefer a 1:1 investment ratio, as they are equally related to offspring of both sexes (r = 0.5). In contrast, helpers should favour an investment ratio of 3:1 towards the production of female brood. This conflict arises because helpers are more closely related to full sisters (r = 0.75) than brothers (r = 0.25). However, helpers should invest relatively more in male brood if relatedness asymmetry within their colony is reduced. This can occur due to queen replacement after colony orphaning, multiple paternity and the presence of unrelated alien helpers. We analysed an unprecedentedly large number of colonies (n = 109) from a UK population of Lasioglossum malachurum, an obligate eusocial sweat bee, to tease apart the effects of these factors on colony-level investment ratios. We found that multiple paternity, unrelated alien helpers and colony orphaning were all common. Queen-right colonies invested relatively more in females than did orphaned colonies, producing a split sex ratio. However, investment ratios did not change due to multiple paternity or the presence of alien helpers, reducing inclusive fitness pay-offs for helpers. Queen control may also have been important: helpers rarely laid male eggs, and investment in female brood was lower when queens were large relative to their helpers. Genetic relatedness between helpers and the brood that they rear was 0.43 in one year and 0.37 in another year, suggesting that ecological benefits, as well as relatedness benefits, are necessary for the maintenance of helping behaviour. Significance statement How helping behaviour is maintained in eusocial species is a key topic in evolutionary biology. Colony-level sex investment ratio changes in response to relatedness asymmetries can dramatically influence inclusive fitness benefits for helpers in eusocial Hymenoptera. The extent to which helpers in primitively eusocial colonies can respond adaptively to different sources of variation in relatedness asymmetry is unclear. Using data from 109 colonies of the sweat bee Lasioglossum malachurum, we found that queen loss, but not multiple paternity or the presence of alien helpers, was correlated with colony sex investment ratios. Moreover, we quantified average helper-brood genetic relatedness to test whether it is higher than that predicted under solitary reproduction (r = 0.5). Values equal to and below r = 0.5 suggest that relatedness benefits alone cannot explain the maintenance of helping behaviour. Ecological benefits of group living and/or coercion must also contribute.

Immature stages and biology of the enigmatic oxyporine rove beetles, with new data on Oxyporus larvae from the Russian Far East (Coleoptera: Staphylinidae)

Oxyporinae are a visually attractive and highly specialized mycophagous subfamily of rove beetles (Staphylinidae) with enigmatic origins and a largely unknown evolutionary history. Our knowledge of their immature stages and biology, valuable for solving questions about their phylogeny, is still very fragmentary. Here, we describe for the first time the larval morphology of Oxyporus (s. str.) procerus Kraatz, 1879 and O. (Pseudoxyporus) melanocephalus Kirschenblatt, 1938, both from the Russian Far East. We redescribe the larval morphology of the widespread O. (s. str.) maxillosus Fabricius, 1775 based on material, also from the Russian Far East. All larvae are identified based on the combined evidence from rearing and cox1 barcoding. For O. maxillosus, O. procerus and O. (P.) melanocephalus we provide some new field and laboratory-based data on feeding, mating, oviposition, female brood care, duration of larval development, and behavior. We applied the Atheta-based system of Ashe & Watrous (1984) to describe and compare the chaetotaxy of these Oxyporus larvae. We extract the most essential comparable data for all species of Oxyporus with known larvae from poorly compatible published larval descriptions with dubious homology assessments for their chaetotaxy. In addition, data on fungal hosts and beetle biology is summarized for the genus and provided for each species. New morphological traits are revealed for the Oxyporus larvae. Significant differences in larval morphology, reproduction behavior and cox1 barcoding region between the subgenera Oxyporus s. str. and Pseudoxyporus Nakane & Sawada, 1956 correspond to the morphological distance between their adults and suggest that they may be potentially elevated to genus rank.

Induced Spawning of Sahar, Tor putitora (Hamilton-Buchanan) in Terai Region of Nepal

Sahar, Tor putitora (Hamilton-Buchanan) is a high valued indigenous riverine species of Nepal. This is declining in its natural habitat. Tor putitora and Tor tor (Hamilton-Buchanan) have been recommended as vulnerable and endangered species. Limited seed production using natural propagation has restricted its expansion in culture as well as rehabilitation in natural waters. The artificial propagation of sahar using synthetic hormone was conducted in Pokhara, AFU, Chitwan and CARP), Kathar during February to April 2017. Sixty five male (0.5-1.8 kg) and forty five female (1.1-2.1 kg) brood fish were reared in 200 m2 earthen ponds at 1000 kg/ha. Fish were fed with 32% crude protein feed at 3% body weight per day. Maturity was observed regularly for softness of the abdomen. Female brood fish with a soft and extended abdomen were injected with synthetic hormone (Ovaprim) at 0.5 ml/kg body weight. Males were not injected hormone. The fertilized eggs were incubated in Atkin hatching trays. A total of 16 females were induced to spawn, and they produced 1630.80±184.30 (mean±SE) eggs per kg body weight. Mean hatching and larval survival rates were 78.4±1.9 and 74.7±1.1%, respectively.

Making the best of a bad job? Chick mortality and flexible female brood care in Snowy Plovers

Offspring desertion represents a trade-off between current and future reproductive success. Its timing is crucial as the termination of parental care has profound consequences for the fitness of the parents and their offspring. However, the decision process involved with termination of care is still poorly understood. Snowy Plovers Charadrius nivosus show highly flexible brood care with females either deserting the brood early or providing care for an extended period. Deserting females often quickly remate and start a new breeding attempt. Using a dynamic modelling framework, we investigated the decision-making process for continuation or termination of care by females over a seven-year period. The length of female care increased over the season likely reflecting lower re-mating opportunities for deserting females late in the season. Present brood size, assessed daily during the brood care period, was strongly related to the length of female care: females were more likely to stay and care for larger than for smaller broods. Chick death and desertion frequently coincided, suggesting that poor offspring condition served as a trigger for female desertion. Overall, deserting females had a similar number of fledglings to caring females. This suggests that for many females, desertion was not a strategy to escape the shackles of monogamy and secure higher reproductive success through sequential polygamy. Rather, most deserting females made the best of a bad job when conditions were poor and their continued presence did not make a difference for the survival of their young. We conclude that when making the decision to continue or terminate care, Snowy Plover females monitor the condition of their offspring closely and adjust their care flexibly to the value and needs of their young.

Phenotype characterization of interspecific hybrid abalone Haliotis asinina and Haliotis squamata seed

<p class="NoParagraphStyle" align="center"><strong>ABSTRACT</strong></p><p class="NoParagraphStyle" align="center"><strong> </strong></p><p class="NoParagraphStyle">Abalone is one of sea-water aquaculture commodity that having relatively low in growth and survival. Interspesific hybridization between abalone <em>Haliotis asinina</em> and <em>Haliotis squamata</em> is required to produce hybrid seeds having a better phenotype inherited from their parents. Crossbreeding of abalone was done in the reciprocal procedure with a natural spawning technique on mass scale. The hybrid seeds showed higher similarity with female brood (98,69%), while the larvae from <em>H. squamata </em>× <em>H. asinina</em> were abnormal on trocophore until early veliger phase then dead occurred the next phase. The results showed that hybridization between male <em>H. asinina</em> and female <em>H. squamata</em> had higher fertilization and hatching rate than its reciprocal i.e. 76.01±6.15% and 60.14±4.80%.</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle">Keywords: interspesific hybridization, phenotype, <em>Haliotis asinina</em>, <em>Haliotis squamata</em>, abalone</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle" align="center"><strong>ABSTRAK</strong></p><p class="NoParagraphStyle" align="center"><strong> </strong></p><p class="NoParagraphStyle">Abalon merupakan komoditas budidaya laut dengan pertumbuhan yang relatif lambat dan kelangsungan hidupnya rendah. Rekayasa persilangan interspesifik antara abalon <em>Haliotis asinina</em> dan <em>Haliotis squamata</em> diharapkan mampu mengatasi permasalahan benih dan memiliki fenotipe unggul yang diwariskan dari tetuanya. Persilangan abalon dilakukan secara resiprok dengan teknik pemijahan alami skala massal. Hasil penelitian menunjukkan bahwa benih hibrida menunjukkan kemiripan dengan induknya sebesar 98,69%, sedangkan larva hibrida antara jantan <em>H. squamata </em>× <em>H. asinina</em> menunjukkan bentuk abnormal pada fase trokofor hingga veliger awal dan kematian pada fase lanjut. Hibridisasi antara jantan <em>H. asinina</em> dan betina <em>H. squamata</em> memiliki derajat pembuahan dan derajat penetasan yang lebih tinggi dibandingkan resiprokalnya, yaitu berturut-turut 76,01±6,15% dan 60,14±4,80%.</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle">Kata kunci: hibridisasi interspesifik, fenotipe, <em>Haliotis asinina</em>, <em>Haliotis squamata</em>, abalon</p><p> </p><p class="NoParagraphStyle" align="center"> </p>