Reproductive cycles of neotropical boid snakes evaluated by ultrasound

Zoo Biology ◽  
2021 ◽  
Author(s):  
Viviane C. Garcia ◽  
Selma Maria Almeida‐Santos
Keyword(s):  
Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 683
Author(s):  
Marc Herremans ◽  
Karin Gielen ◽  
Jos Van Kerckhoven ◽  
Pieter Vanormelingen ◽  
Wim Veraghtert ◽  
...  

The peacock butterfly is abundant and widespread in Europe. It is generally believed to be univoltine (one generation per year): adults born in summer overwinter and reappear again in spring to reproduce. However, recent flight patterns in western Europe mostly show three peaks during the year: a first one in spring (overwintering butterflies), a second one in early summer (offspring of the spring generation), and a third one in autumn. It was thus far unclear whether this autumn flight peak was a second new generation or consisted of butterflies flying again in autumn after a summer rest (aestivation). The life cycle of one of Europe’s most common butterflies is therefore still surprisingly inadequately understood. We used hundreds of thousands of observations and thousands of pictures submitted by naturalists from the public to the online portal observation.orgin Belgium and analyzed relations between flight patterns, condition (wear), reproductive cycles, peak abundances, and phenology to clarify the current life history. We demonstrate that peacocks have shifted towards two new generations per year in recent decades. Mass citizen science data in online portals has become increasingly important in tracking the response of biodiversity to rapid environmental changes such as climate change.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vanessa Robitzch ◽  
Victor Molina-Valdivia ◽  
Jaiber J. Solano-Iguaran ◽  
Mauricio F. Landaeta ◽  
Michael L. Berumen

AbstractVery little is known about the ecology and biology of the smallest marine vertebrates, fishes in the genus Schindleria. Even though over half of named Schindleria species have been identified in the Red Sea, the collection of only very few specimens has been documented. Here, we assessed abundance patterns of nearly two thousand Red Sea long dorsal fin (LDF) adults and found evidence for putative seasonal and spatial differences, likely related to differing habitat and environmental conditions. The highest abundances were outside local seasonal temperature extremes and decoupled from peaks of coral reef fish recruitment. We also found evidence for global trends in abundances related to lunar cycles using our Red Sea data and that from a recently published large collection of specimens from the DANA Expedition (1928–1930). The abundance of adult LDF Schindleria in relation to lunar phases differed significantly, with most Schindleria caught outside the full moon, and mostly during the new moon in the Red Sea and the 3rd quarter moon in the DANA collection. We further suggest that the abundances of Schindleria at coral reefs may be related to reproductive cycles and that these cycles may be timed with the moon as back-calculations of hatch dates from otoliths from the Red Sea significantly resulted after the new moon, making Schindleria the fastest-lived coral reef fish with the shortest generation times. Schindleria could be the most numerous coral reef fish in the world, for which we encourage increased research.


Coral Reefs ◽  
2021 ◽  
Author(s):  
Crystal J. McRae ◽  
Wen-Bin Huang ◽  
Tung-Yung Fan ◽  
Isabelle M. Côté

AbstractOcean warming induced by climate change is the greatest threat to the persistence of coral reefs globally. Given the current rate of ocean warming, there may not be sufficient time for natural acclimation or adaptation by corals. This urgency has led to the exploration of active management techniques aimed at enhancing thermal tolerance in corals. Here, we test the capacity for transgenerational acclimation in the reef-building coral Pocillopora acuta as a means of increasing offspring performance in warmer waters. We exposed coral colonies from a reef influenced by intermittent upwelling and constant warm-water effluent from a nuclear power plant to temperatures that matched (26 °C) or exceeded (29.5 °C) season-specific mean temperatures for three reproductive cycles; offspring were allowed to settle and grow at both temperatures. Heated colonies reproduced significantly earlier in the lunar cycle and produced fewer and smaller planulae. Recruitment was lower at the heated recruitment temperature regardless of parent treatment. Recruit survival did not differ based on parent or recruitment temperature. Recruits from heated parents were smaller and had lower maximum quantum yield (Fv/Fm), a measurement of symbiont photochemical performance. We found no direct evidence that thermal conditioning of adult P. acuta corals improves offspring performance in warmer water; however, chronic exposure of parent colonies to warmer temperatures at the source reef site may have limited transgenerational acclimation capacity. The extent to which coral response to this active management approach might vary across species and sites remains unclear and merits further investigation.


2021 ◽  
Vol 43 (3) ◽  
Author(s):  
Nick Hopwood ◽  
Staffan Müller-Wille ◽  
Janet Browne ◽  
Christiane Groeben ◽  
Shigehisa Kuriyama ◽  
...  

AbstractWe invite systematic consideration of the metaphors of cycles and circulation as a long-term theme in the history of the life and environmental sciences and medicine. Ubiquitous in ancient religious and philosophical traditions, especially in representing the seasons and the motions of celestial bodies, circles once symbolized perfection. Over the centuries cyclic images in western medicine, natural philosophy, natural history and eventually biology gained independence from cosmology and theology and came to depend less on strictly circular forms. As potent ‘canonical icons’, cycles also interacted with representations of linear and irreversible change, including arrows, arcs, scales, series and trees, as in theories of the Earth and of evolution. In modern times life cycles and reproductive cycles have often been held to characterize life, in some cases especially female life, while human efforts selectively to foster and disrupt these cycles have harnessed their productivity in medicine and agriculture. But strong cyclic metaphors have continued to link physiology and climatology, medicine and economics, and biology and manufacturing, notably through the relations between land, food and population. From the grand nineteenth-century transformations of matter to systems ecology, the circulation of molecules through organic and inorganic compartments has posed the problem of maintaining identity in the face of flux and highlights the seductive ability of cyclic schemes to imply closure where no original state was in fact restored. More concerted attention to cycles and circulation will enrich analyses of the power of metaphors to naturalize understandings of life and their shaping by practical interests and political imaginations.


2016 ◽  
Vol 225 ◽  
pp. 95-103 ◽  
Author(s):  
Serena A. Barnes ◽  
J. Andrew Teare ◽  
Sheryl Staaden ◽  
Lara Metrione ◽  
Linda M. Penfold

2007 ◽  
Vol 27 (11) ◽  
pp. 4105-4120 ◽  
Author(s):  
Stefan Lim ◽  
Min Luo ◽  
Mingshi Koh ◽  
Meng Yang ◽  
Mohammed Nizam bin Abdul Kadir ◽  
...  

ABSTRACT The gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are produced in the embryonic pituitary in response to delivery of the hypothalamic gonadotropin releasing hormone (GnRH). GnRH has a pivotal role in reestablishing gonadotropin levels at puberty in primates, and for many species with extended reproductive cycles, these are reinitiated in response to central nervous system-induced GnRH release. Thus, a clear role is evident for GnRH in overcoming repression of these genes. Although the mechanisms through which GnRH actively stimulates LH and FSH β-subunit (FSHβ) gene transcription have been described in some detail, there is currently no information on how GnRH overcomes repression in order to terminate reproductively inactive stages. We show here that GnRH overcomes histone deacetylase (HDAC)-mediated repression of the gonadotropin β-subunit genes in immature gonadotropes. The repressive factors associated with each of these genes comprise distinct sets of HDACs and corepressors which allow for differentially regulated derepression of these two genes, produced in the same cell by the same regulatory hormone. We find that GnRH activation of calcium/calmodulin-dependent protein kinase I (CaMKI) plays a crucial role in the derepression of the FSHβ gene involving phosphorylation of several class IIa HDACs associated with both the FSHβ and Nur77 genes, and we propose a model for the mechanisms involved. In contrast, derepression of the LH β-subunit gene is not CaMK dependent. This demonstration of HDAC-mediated repression of these genes could explain the temporal shut-down of reproductive function at certain periods of the life cycle, which can easily be reversed by the actions of the hypothalamic regulatory hormone.


2008 ◽  
Vol 42 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Maria Helena Leclair ◽  
Marc Levasseur ◽  
Raymond Leclair

Author(s):  
Mourad Guettaf ◽  
Gustavo A. San Martin ◽  
Patrice Francour

The spawning of Paracentrotus lividus has been determined on the basis of the annual gonad index cycle at three sites in the Algiers area presenting low, intermediate and strong hydrodynamism. Three biotopes (Posidonia oceanica beds, rocky substrate with photophilous algae and overgrazed rocky substrate) and two depths (1–3 m and 6–10 m) were considered at these sites, the sex-ratio was always strongly in favour of females (2:1 to 3:1). In all sites but one, there were marked differences in the gonad index and the spawning period between sites; the gonad index reached its maximum value at the site with the weakest hydrodynamism, and the minimum value at the site with the strongest hydrodynamism. Spawning took place in April–May and August–September at the site with the weakest hydrodynamism, in April–June and October–December at the site with intermediate hydrodynamism and only in winter at the site with maximum hydrodynamism. The coexistence, on regional scale, of these reproductive cycles might enable Paracentrotus lividus to compensate the mortality during planktonic larval phase by the fact that spawning of this sea urchin occurred in all seasons.


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