Reproductive-Biology of Megascolides Australis Mccoy (Oligochaeta, Megascolecidae)

1995 ◽  
Vol 43 (5) ◽  
pp. 489 ◽  
Author(s):  
BD Vanpraagh
Keyword(s):  
Life History ◽  
Reproductive Biology ◽  
Reproductive Strategies ◽  
Egg Laying ◽  
Dispersal Ability ◽  
Low Density ◽  
Spermathecal Duct ◽  
Dispersal Abilities ◽  
Reproductive Processes

Observations of gametogenesis facilitated understanding life history and reproductive processes in Megascolides australis, whose reproductive strategies are correlated with longevity, low density and poor dispersal ability. Worms are biparental and have a discrete breeding (egg laying) season in spring and summer. This coincides with the greatest number of mature ova and the glandular epidermis of the clitellar region being thickest. Gametogenesis occurs throughout the year, with sperm present in the spermathecae and available on male funnels ail year. Non-seasonal copulation may occur when two worms meet and conditions are favourable; this trait is advantageous for species in low densities with poor dispersal abilities. The spermathecal structure of M. australis differs from that of other megascolecids recorded in that the structure of the diverticulum includes many multiloculate chambers that do not connect directly with the spermathecal duct. The sperm form orientated bundles (spermatozeugmata) not previously described for Megascolecidae and are stored in the ampulla rather than the diverticula.

Laboratory Studies on the Effects of Different Natural Foods on the Reproductive Biology of Lygaeus equestris (L.) (Het. Lygaeidae)

1974 ◽  
Vol 4 (3) ◽  
pp. 181-190 ◽  
Author(s):  
OTTO KUGELBERG
Keyword(s):  
Reproductive Biology ◽  
Reproductive Strategies ◽  
Egg Laying ◽  
Food Plants ◽  
Reproductive Diapause ◽  
Laboratory Studies ◽  
Mating Activity ◽  
Natural Foods ◽  
Ovary Maturation ◽  
Lygaeus Equestris

Abstract The reproductive biology of the seed-feeding bug Lygaeus equestris in the laboratory is described and the suitability of different kinds of seeds for reproductive success are compared. A relationship exists between the duration of reproductive diapause in the field and the subsequent reactivation time in the laboratory. Mating activity starts irrespective of presence of food. Matings or presence of males are, in contrast to feeding, not necessary for ovary maturation and egg-laying. Hatchable eggs were produced on all diets tested. There were significant differences in length of the oviposition period, longevity and number of eggs laid or hatched in females fed on the different diets. The importance of different food plants for the reproductive strategies of the bug in Sweden is discussed.

scholarly journals Breeding biology of the Green-backed Tit (Parus monticolus) in southwest China

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ping Ye ◽  
Xiaogang Yao ◽  
Jianli Bi ◽  
Guangrong Li ◽  
Wei Liang ◽  
...  
Keyword(s):  
Life History ◽  
Reproductive Strategies ◽  
Southwest China ◽  
Parental Behavior ◽  
Egg Laying ◽  
Breeding Biology ◽  
Life History Strategies ◽  
Reproductive Outcome ◽  
Behavioral Patterns ◽  
Evolution Of Life

AbstractStudies on breeding biology enable us to broaden our understanding of the evolution of life history strategies. We studied the breeding biology of the Green-backed Tit (Parus monticolus) to provide comprehensive data on nest and egg characteristics, parental behavior throughout egg laying and nestling periods, and reproductive outcome. Our study reveals adaptive behavioral patterns and reproductive strategies for P. monticolus.

scholarly journals Reproductive biology of Synallaxis albescens (Aves: Furnariidae) in the cerrado of central Brazil

2012 ◽  
Vol 12 (4) ◽  
pp. 266-269 ◽  
Author(s):  
Miguel Ângelo Marini ◽  
Sheila Silva Rodrigues ◽  
Mariana Batista Silveira ◽  
Harold Francis Greeney
Keyword(s):  
Life History ◽  
Reproductive Biology ◽  
Reproductive Strategies ◽  
Life History Evolution ◽  
Average Height ◽  
Central Theme ◽  
Central Brazil ◽  
Nestling Period ◽  
Nesting Substrate ◽  
Breeding Seasons

Understanding the causes and consequences of variation in reproductive strategies is a central theme in studies of avian life history evolution. This study describes the reproductive biology of Synallaxis albescens (Furnariidae) in the cerrado biome of central Brazil. We monitored 35 nests during the 2003 to 2011 breeding seasons, visiting them every 2-4 days. Synallaxis albescens breeds from mid-September to mid-January, builds a retort-shaped nest, and generally lays three immaculate white eggs. Eggs weighed 1.75 g and measured 19.7 by 14.4 mm. Most nests studied were in open cerrado or shrub grassland at an average height above the ground of 0.3 m, with a preference for Davilla elliptica (Dilleniaceae) shrubs as a nesting substrate. Incubation period averaged 18.1 days, while the nestling period averaged 13.6 days. Of 16 closely monitored nests, four were successful (25%), 11 were depredated (69%), and one was abandoned. Predation was similar during incubation (45%) and nestling (55%) phases. In general, the breeding biology of S. albescens was similar to that described previously for this species and for related Furnariidae.

Dinosaur Macroevolution and Macroecology

2018 ◽  
Vol 49 (1) ◽  
pp. 379-408 ◽  
Author(s):  
Roger B.J. Benson
Keyword(s):  
Life History ◽  
Body Size ◽  
Reproductive Biology ◽  
Fossil Record ◽  
Structural Diversity ◽  
Body Plan ◽  
Adaptive Landscape ◽  
Species Diversification ◽  
Size Evolution ◽  
Body Size Evolution

Dinosaurs were large-bodied land animals of the Mesozoic that gave rise to birds. They played a fundamental role in structuring Jurassic–Cretaceous ecosystems and had physiology, growth, and reproductive biology unlike those of extant animals. These features have made them targets of theoretical macroecology. Dinosaurs achieved substantial structural diversity, and their fossil record documents the evolutionary assembly of the avian body plan. Phylogeny-based research has allowed new insights into dinosaur macroevolution, including the adaptive landscape of their body size evolution, patterns of species diversification, and the origins of birds and bird-like traits. Nevertheless, much remains unknown due to incompleteness of the fossil record at both local and global scales. This presents major challenges at the frontier of paleobiological research regarding tests of macroecological hypotheses and the effects of dinosaur biology, ecology, and life history on their macroevolution.

scholarly journals Host–parasitoid evolution in a metacommunity

2016 ◽  
Vol 283 (1831) ◽  
pp. 20160477 ◽  
Author(s):  
Denon Start ◽  
Benjamin Gilbert
Keyword(s):  
Natural Enemies ◽  
Patch Size ◽  
Common Garden ◽  
Species Traits ◽  
Dispersal Ability ◽  
Isolated Populations ◽  
Selection Gradient ◽  
Phenotypic Differences ◽  
Dispersal Abilities ◽  
Phenotypic Shift

Patch size and isolation are predicted to alter both species diversity and evolution; yet, there are few empirical examples of eco-evolutionary feedback in metacommunities. We tested three hypotheses about eco-evolutionary feedback in a gall-forming fly, Eurosta solidaginis and two of its natural enemies that select for opposite traits: (i) specialization and poor dispersal ability constrain a subset of natural enemies from occupying small and isolated patches, (ii) this constraint alters selection on the gall fly, causing phenotypic shifts towards traits resistant to generalist and dispersive enemies in small and isolated patches, and (iii) reduced dispersal evolves in small, isolated populations. We sampled patches in a natural metacommunity and found support for all hypotheses; Eurosta 's specialist wasp parasitoid attacked fewer galls in small and isolated patches, generating a selection gradient that favoured small galls resistant to predation by a dispersive and generalist bird predator. Phenotype distributions matched this selection gradient, and these phenotypic differences were maintained in a common garden experiment. Finally, we found lower dispersal abilities in small and isolated patches, a phenotypic shift that aids in the maintenance of local adaptation. We suggest that the trophic rank and the species traits of consumers are central to evolution in metacommunities.

scholarly journals Uterine fluid composition of the dwarf ornate wobbegong shark (Orectolobus ornatus) during gestation

2011 ◽  
Vol 62 (6) ◽  
pp. 576 ◽  
Author(s):  
Megan T. Ellis ◽  
Nicholas M. Otway
Keyword(s):  
Reproductive Biology ◽  
Coastal Waters ◽  
Reproductive Strategies ◽  
Yolk Sac ◽  
Gestation Period ◽  
Fluid Composition ◽  
Complex Composition ◽  
Eastern Australia ◽  
Uterine Fluid ◽  
Low Levels

Low fecundity in chondrichthyans makes them extremely susceptible to fishing, so understanding the various reproductive strategies in this group is vital for management. Knowledge of the uterine fluid (UF) composition throughout gestation is fundamental to this understanding, yet is restricted to a few species. This study focussed on the UF composition of the wobbegong (Orectolobus ornatus), which inhabits coastal waters off eastern Australia. The UF was quantified throughout pregnancy. Fluids surrounding uterine eggs had a complex composition, with mean urea (98.48 mmol L–1), sodium (560.25 mmol L–1) and potassium (13.93 mmol L–1) concentrations significantly greater than those in seawater. A change in composition, from complex to simple, occurred after 3–4 months gestation. Major electrolyte concentrations then resembled seawater for the remainder of gestation, suggesting the flushing of the uteri with seawater and evidenced by fluctuating low levels of urea. The gestation period reflected the time for metabolism of yolk stores, osmotic and ionic adjustment, development of functioning immunological systems and prevention of external yolk sac damage. Our study is the first documentation of UF composition for a wobbegong shark and increases understanding of its reproductive biology.

scholarly journals Reproductive biology of Sympterygia bonapartii (Chondrichthyes: Rajiformes: Arhynchobatidae) in San Matías Gulf, Patagonia, Argentina

2017 ◽  
Vol 15 (1) ◽  
Author(s):  
María L. Estalles ◽  
María R. Perier ◽  
Edgardo E. Di Giácomo
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Biology ◽  
Early Spring ◽  
Egg Laying ◽  
Reproductive Pattern ◽  
Reproductive Parameters ◽  
Egg Capsules ◽  
Northern Patagonia ◽  
Total Length

ABSTRACT This study estimates and analyses the reproductive parameters and cycle of Sympterygia bonapartii in San Matías Gulf, northern Patagonia, Argentina. A total of 827 males and 1,299 females were analysed. Males ranged from 185 to 687 mm of total length (TL) and females from 180 to 742 mm TL. Sexual dimorphism was detected; females were larger, heavier, exhibited heavier livers, wider discs and matured at lager sizes than males. Immature females ranged from 180 to 625 mm TL, maturing females from 408 to 720 mm TL, mature ones from 514 to 742 mm TL and females with egg capsules from 580 to 730 mm TL. Immature males ranged from 185 to 545 mm TL, maturing ones from 410 to 620 mm TL and mature males from 505 to 687 mm TL. Size at which 50% of the skates reached maturity was estimated to be 545 mm TL for males and 594 mm TL for females. According to the reproductive indexes analysed, S. bonapartii exhibited a seasonal reproductive pattern. Mating may occur during winter-early spring and the egg-laying season, during spring and summer.

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