scholarly journals Ancient androdioecy in the freshwater crustacean Eulimnadia

2005 ◽  
Vol 273 (1587) ◽  
pp. 725-734 ◽  
Author(s):  
Stephen C Weeks ◽  
Thomas F Sanderson ◽  
Sadie K Reed ◽  
Magdalena Zofkova ◽  
Brenton Knott ◽  
...  
Keyword(s):  
Life History ◽  
Mating System ◽  
Breeding System ◽  
Living Systems ◽  
System Evolution ◽  
Mating System Evolution ◽  
History Of ◽  
Freshwater Crustacean ◽  
Males And Females

Among the variety of reproductive mechanisms exhibited by living systems, one permutation—androdioecy (mixtures of males and hermaphrodites)—is distinguished by its rarity. Models of mating system evolution predict that androdioecy should be a brief stage between hermaphroditism and dioecy (separate males and females), or vice versa. Herein we report evidence of widespread and ancient androdioecy in crustaceans in the genus Eulimnadia , based on observations of over 33 000 shrimp from 36 locations from every continent except Antarctica. Using phylogenetic, biogeographical and palaeontological evidence, we infer that androdioecy in Eulimnadia has persisted for 24–180 million years and has been maintained through multiple speciation events. These results suggest that androdioecy is a highly successful aspect of the life history of these freshwater crustaceans, and has persisted for orders of magnitude longer than predicted by current models of this rare breeding system.

scholarly journals Mating-System Evolution: Rise of the Irresistible Males

2010 ◽  
Vol 20 (11) ◽  
pp. R482-R484 ◽  
Author(s):  
John R. Pannell ◽  
Grazyna Korbecka
Keyword(s):  
Mating System ◽  
System Evolution ◽  
Mating System Evolution

The Life History and Habits of Chrysomela crotchi Brown (Coleoptera: Chrysomelidae) in Northwestern Ontario

1965 ◽  
Vol 97 (5) ◽  
pp. 541-549 ◽  
Author(s):  
E. P. Smereka
Keyword(s):  
Life History ◽  
Adult Stage ◽  
Egg Mass ◽  
Predator Species ◽  
Control Factors ◽  
Northwestern Ontario ◽  
History Of ◽  
Males And Females ◽  
Overwintering Mortality ◽  
Larval Parasites

AbstractThe life history of Chrysomela crotchi, a univoltine species commonly found on trembling aspen, was studied in northwestern Ontario from 1959 to 1962. The most striking feature of its life history was the longevity of adults, which were capable of overwintering two successive years. Overwintered adults became active and began feeding in late May, and oviposition occurred from early June to late July. The incubation period was approximately 10 days and the three larval instars required approximately one month for development to the adult stage.Females laid more eggs during their second season and the highest number laid was 326. The number of eggs in an egg mass averaged 37.6, and the average interval between the deposition of egg masses was 4 days. Males and females mated more than once, but only one mating was necessary for a female to produce viable eggs throughout the season. Males were capable of fertilizing more than one female and remained potent for more than one season.Parasitism was low, and only two species of larval parasites were reared. Several predator species were observed preying on the immature stages. Predation and overwintering mortality appeared to be the most important control factors.

scholarly journals Social Games and Genic Selection Drive Mammalian Mating System Evolution and Speciation

2020 ◽  
Vol 195 (2) ◽  
pp. 247-274
Author(s):  
Barry Sinervo ◽  
Alexis S. Chaine ◽  
Donald B. Miles
Keyword(s):  
Mating System ◽  
Social Games ◽  
System Evolution ◽  
Mating System Evolution

Maturation, reproduction and early life history of anglerfish Lophius piscatorius in Faroese waters

2015 ◽  
Vol 60 ◽  
pp. 114 ◽  
Author(s):  
Lise H. Ofstad ◽  
Torstein Petersen ◽  
Petur Steingrund
Keyword(s):  
Life History ◽  
Early Life ◽  
Early Life History ◽  
Nursery Ground ◽  
Life Stages ◽  
Morphological Transformation ◽  
Spawning Areas ◽  
History Of ◽  
Males And Females ◽  
First Maturity

<p>Maturation, reproduction and early life history of <em>Lophius piscatorius </em>was investigated in Faroese waters. Length at first maturity (L50) was 58 cm for males and 84 cm for females, corresponding to an age of about four years for males and seven years for females. The proportions of females and males were similar in fish less than 55 cm long, and were skewed towards more males in medium sized fish (55–75  cm).  Females  were  predominant  in the larger fish (&gt; 85 cm). Observations of spawning males and females, egg ribbons and pelagic anglerfish larvae, suggest that the main spawning season is from February to April and the spawning area seems to be southwest of the Faroe Plateau and in the Faroe Bank area. The Faroe Plateau probably serves as a nursery ground for juvenile anglerfish. Morphological transformation from larvae to juveniles occurred when the fish were about 7–9 cm long and they settled to the bottom when they were about 11 cm long. Thus, all life stages, as well as nursery areas, spawning areas and feeding areas of anglerfish are found in Faroese waters, indicating a separate stock in the area.</p>

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