scholarly journals Coordination of Reproductive Activity in Aplysia: Peptide Neurohormones, Neurotransmitters, and Pheromones Encoded by the Egg-Laying Hormone Family of Genes

1992 ◽  
Vol 183 (1) ◽  
pp. 165-172 ◽  
Author(s):  
S. D. Painter
Keyword(s):  
Reproductive Activity ◽  
Egg Laying

scholarly journals Direct assessment of queen quality and lack of worker suppression in a paper wasp

2005 ◽  
Vol 272 (1570) ◽  
pp. 1339-1344 ◽  
Author(s):  
Jürgen Liebig ◽  
Thibaud Monnin ◽  
Stefano Turillazzi
Keyword(s):  
Reproductive Output ◽  
Ovarian Development ◽  
Inclusive Fitness ◽  
Reproductive Activity ◽  
Egg Laying ◽  
Paper Wasp ◽  
Polistes Dominulus ◽  
Queen Policing ◽  
Reproductive Conflicts ◽  
Animal Societies

Assessing a conspecific's potential is often crucial to increase one's fitness, e.g. in female choice, contests with rivals or reproductive conflicts in animal societies. In the latter, helpers benefit from accurately assessing the fertility of the breeder as an indication of inclusive fitness. There is evidence that this can be achieved using chemical correlates of reproductive activity. Here, we show that queen quality can be assessed by directly monitoring her reproductive output. In the paper wasp Polistes dominulus , we mimicked a decrease in queen fertility by regularly removing brood. This triggered ovarian development and egg-laying by many workers, which strongly suggests that brood abundance is a reliable cue of queen quality. Brood abundance can be monitored when workers perform regular brood care in small size societies where each brood element is kept in a separate cell. Our results also show that although the queen was not manipulated, and thus remained healthy and fully fertile, she did not control worker egg-laying. Nevertheless, when workers laid eggs, the queen secured a near reproductive monopoly by selectively destroying these eggs, a mechanism known as ‘queen policing’. By contrast, workers destroyed comparatively few queen-laid eggs, but did destroy each other's eggs.

scholarly journals Upper Carboniferous ammonoid embryonic shell clusters: transported accumulation or in situ nests?

1992 ◽  
Vol 6 ◽  
pp. 196-196 ◽  
Author(s):  
Royal H. Mapes ◽  
Kazushige Tanabe ◽  
Neil H. Landman ◽  
Curtis J. Faulkner
Keyword(s):  
Biological Activities ◽  
Reproductive Activity ◽  
Egg Laying ◽  
Upper Carboniferous ◽  
Carbonate Concretions ◽  
Embryonic Shell ◽  
Storm Deposits ◽  
Dinosaur Eggs ◽  
Shell Fragments

Clusters of ammonoid embryonic shells have been discovered in several carbonate concretions from a dysoxic, relatively deep water shale (Heebner Shale-Oread Formation) of Virgilian (U. Carboniferous) age near the community of Pomona, Kansas. The concretions from a single outcrop display four distinct units. Unit 1 is the lowest unit and has an evenly laminated fabric with scattered embryonic and juvenile ammonoids, gastropods, and bivalves. The bedding fabric of this unit is interrupted and truncated by a series of pits that form the base of Unit 2, which is a sharply bounded discontinuity. Within the pits there are embryonic ammonoid clusters up to 2.5 cm thick containing as many as 250 individuals per cm3. Some juvenile ammonoids and shell fragments (mostly of ammonoids) are also present. These clusters are capped by Unit 3 which has a gradational boundary with Unit 2. Unit 3 consists in places of a packstone of fossil debris including ammonoid body chamber and phragmocone fragments, three genera of juvenile ammonoids, embryonic ammonoids, and more rarely brachiopods, bivalves, and orthoconic nautiloids. Elsewhere, fossils of Unit 3 are well separated by matrix, which lacks the bedding fabric characteristic of Unit 1. The ammonoids in Unit 3 include mature to sub-mature fragments of Aristoceras and sub-mature phragmocones of Glaphyrites and Shumardites. The brachiopods (articulate and inarticulate) and the bivalves are probably sub-mature or mature. Planktonic bivalves are extremely rare. The number of shell fragments of embryonic and postembryonic ammonoids and other shell fragments decreases upwards from the upper contact of Unit 2. The boundary of Units 3 and 4 is more-or-less gradational; Unit 4 has a sedimentary fabric and faunal content like that observed in Unit 1.One set of hypotheses to explain the embryo clusters in Unit 2 emphasizes sedimentological processes such as selective transportation and accumulation by currents, turbidity transport and storm deposits. Another set of hypotheses favors biological activities such as reproductive activity and egg-laying. If this second set of hypotheses is correct, these clusters would provide the first documentation of ammonoid reproductive activity and would represent a find as significant in its way as that of the nests of embryo bearing dinosaur eggs.

Mise en évidence et évolution, au cours du cycle biologique, de neurones producteurs d'une substance apparentée à la motiline porcine dans le ganglion supraoesophagien de la sangsue Theromyzon tessulatum

1989 ◽  
Vol 67 (3) ◽  
pp. 636-640 ◽  
Author(s):  
J. Malecha ◽  
M. Verger-Bocquet ◽  
G. Tramu
Keyword(s):  
Life Cycle ◽  
Reproductive Activity ◽  
Egg Laying ◽  
Feeding Pattern ◽  
Cycle Biologique ◽  
Supraesophageal Ganglion

The life cycle of Theromyzon tessulatum has been divided into stages defined on the basis of feeding pattern and reproductive activity. The use of an antiserum raised against porcine motilin demonstrated the presence of immunoreactive cells and fibers in the supraesophageal ganglion throughout the life of the leech. Immunopositive fibers are present in the neurohemal area of the dorsal commissure. The highest number of immunopositive neurons is found during stages 3B, 3C, and 3D, which precede egg-laying. The control of oogenesis by a substance related to porcine motilin is postulated.

scholarly journals Why do mayflies lay their eggs en masse on dry asphalt roads? Water-imitating polarized light reflected from asphalt attracts Ephemeroptera.

1998 ◽  
Vol 201 (15) ◽  
pp. 2273-2286 ◽  
Author(s):  
G Kriska ◽  
G Horváth ◽  
S Andrikovics
Keyword(s):  
Polarized Light ◽  
Reproductive Activity ◽  
Egg Laying ◽  
Degree Of Polarization ◽  
The Road ◽  
Large Numbers ◽  
Reflected Light ◽  
Polarization Characteristics ◽  
Higher Temperature ◽  
Great Danger

We report on dry asphalt roads acting as 'mayfly traps'; that is, they lure swarming, mating and egg-laying mayflies in large numbers. To explain this surprising behaviour, we performed multiple-choice experiments with Ephemeroptera in the field, and measured and compared the reflection-polarization characteristics of an asphalt road and a mountain creek from which mayflies emerge. We show here that Ephemeroptera can be deceived by and attracted to dry asphalt roads because of the strongly horizontally polarized light reflected from the surface. Asphalt surfaces can mimic a highly polarized water surface to Ephemeroptera. The darker and smoother the asphalt surface, the higher is the degree of polarization of reflected light and the more attractive is the road to mayflies. We show that mayflies detect water by means of polarotaxis; that is, on the basis of the partially and horizontally polarized reflected light. Asphalt roads are excellent markers for swarming Ephemeroptera because of their conspicuous elongated form; the sky above them is usually open, which is the prerequisite of mayfly mating, and the higher temperature of the asphalt prolongs the reproductive activity of mayflies. These additional factors enhance the attractiveness of asphalt roads to swarming mayflies. Thus, asphalt roads near ephemeropteran emergence sites (lakes, rivers and creeks) are a great danger for mayflies, because eggs laid on the asphalt inevitably perish. Asphalt roads can deceive and attract mayflies en masse like the ancient tar pits and asphalt seeps or the recent crude or waste oil lakes deceive, lure and trap polarization-sensitive water-seeking insects in large numbers.

scholarly journals Reproductive activity of the frog Dendrobates auratus Girard in captivity breeding

2010 ◽  
Vol 58 (5) ◽  
pp. 209-222
Author(s):  
Romana Křížová
Keyword(s):  
Mortality Rate ◽  
Total Duration ◽  
Total Mortality ◽  
Reproductive Activity ◽  
Egg Laying ◽  
The Family ◽  
New Knowledge ◽  
In Captivity ◽  
Dendrobates Auratus ◽  
Duration Of Development

Research of the reproduction activities of Dendrobates auratus Girard, 1855 is part of a broader ana­ly­sis of the problems encountered when keeping frogs from the family Dendrobatidae in captivity. The aim is to achieve an optimization of measures for successful breeding of these amphibians, for both the amateur hobbyist and conservationist alike. Due to the wide area they have colonized, many colour variations exist; the reproduction parameters of six differently coloured examples of the species were tracked. The collection of data happened in standardized conditions over two consecutive years (2007, 2008) and was aimed at measuring five indicators concerning reproduction, understanding of egg-laying dynamics during a year, measuring the risk of stock loss during different stages of development and determining if any differences existed between the different colour variations in these parameters. A noticable alternating cycle of rest and reproduction activities has been observed between equinoxes. In the harvest there were usually 5–10 eggs with an average incubation period of 10 days (8–18) at a temperature of 22 °C. The total duration of development was on average 74 days (64–103). The number of eggs in a harvest and the duration of incubation were statistically dif­fe­rent with the blue form between different observed periods. Total mortality rate during ontogenesis reached 10–53%, the highest losses were in the period when the tadpole left its egg and began developing its hind legs, 5–60%. The optimisation of breeding conditions has been reccommended. Secondary be­ne­fits of this study research was the collection of new knowledge about ethology of this species in captivity.

Experimental increase in female mass during the fertile phase leads to enhanced extra-pair paternity in pied flycatchers Ficedula hypoleuca

2019 ◽  
Author(s):  
Mireia Plaza ◽  
Alejandro Cantarero ◽  
Juan Moreno
Keyword(s):  
Negative Relationship ◽  
Ficedula Hypoleuca ◽  
Egg Laying ◽  
Female Dominance ◽  
Laying Date ◽  
Control Group ◽  
Wing Loading ◽  
Potential Fecundity ◽  
Fertile Phase ◽  
Extra Pair Paternity

Female mass in most altricial birds reaches its maximum during breeding at egg-laying, which coincides temporally with the fertile phase when extra-pair paternity (EPP) is determined. Higher mass at laying may have two different effects on EPP intensity. On the one hand, it would lead to increased wing loading (body mass/wing area), which may impair flight efficiency and thereby reduce female’s capacity to resist unwanted extra-pair male approaches (sexual conflict hypothesis). On the other hand, it would enhance female condition, favouring her capacity to evade mate-guarding and to search for extra-pair mates (female choice hypothesis). In both cases, higher female mass at laying may lead to enhanced EPP. To test this prediction, we reduced nest building effort by adding a completely constructed nest in an experimental group of female pied flycatchers (Ficedula hypoleuca). Our treatment caused an increase in mass and thereby wing loading and this was translated into a significantly higher EPP in the manipulated group compared with the control group as expected. There was also a significant negative relationship between EPP and laying date and the extent of the white wing patch, an index of female dominance. More body reserves at laying mean not only a higher potential fecundity but a higher level of EPP as well. This interaction had not previously received due attention but should be considered in future studies of avian breeding strategies.

Elevated nest predation risk promotes offspring size variation in birds with prolonged parental care.

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Predation Risk ◽  
Reproductive Cycle ◽  
Perceived Risk ◽  
Nest Predation ◽  
Bird Species ◽  
Size Variation ◽  
Egg Laying ◽  
Offspring Size ◽  
Natural Predation ◽  
Risk Spreading

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.

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