Results 161 to 170 of about 1,468 (192)

Protandry in Teredo Norvegica

Journal of Cell Science, 1926
ABSTRACT Although in the accounts of the Teredinidae given by Caiman (1) and others it is stated that some species are reported to be hermaphrodite while in others the sexes are separate, so far as I have been able to discover the only species which up to the present has been shown to be hermaphrodite is Xylotrya gouldii.
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Models for the evolution of protandry in insects

Theoretical Population Biology, 1983
Abstract Protandry is the tendency for males to emerge before females, and it is common in insects with discrete, nonoverlapping generations in which females mate once only soon after emergence. In these circumstances males which emerge early will have more opportunities to mate than those which emerge late, so that protandry would be expected to ...
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Polyandry and protandry in butterflies

Bulletin of Mathematical Biology, 1992
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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Protandry of the flathead Suggrundus meerdervoortii (Teleostei: Platycephalidae)

Ichthyological Research, 2018
Suggrundus meerdervoortii (Platycephalidae) has been hypothesized to pass through four phases, thus changing sex three times: the first male, first female, second male and second female phases. In this study, gonads of males and females were constructed from developed testis with an immature ovary and only oocytes, respectively.
Toshiaki Shitamitsu, Tomoki Sunobe
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Plasticity of gonadal development and protandry in fishes

Journal of Experimental Zoology, 1992
AbstractSexual differentiation in eutherian mammals follows a simple governing paradigm: development proceeds in a female direction unless a masculinizing mechanism intervenes. Sexual development in fishes is much more plastic than in mammals. It permits the intervention of environmental factors and follows several different types of sequences that ...
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Models on butterfly protandry: Virgin females are at risk to die

Theoretical Population Biology, 1991
Current models on protandry in butterflies assume that females are mated instantaneously upon eclosion. However, for most butterfly species this assumption is not realistic. In this paper a model is formulated in which the mating rate depends on both male and female density.
Zonneveld, C., Metz, J. A. J.
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Protandry and Moulting to Maturity in the Spider Pityohyphantes phrygianus

Oikos, 1990
In natural populations in SW Sweden, the overwintering subadult specimens of the sheetweb spider Pityohyphantes phrygianus (C. L. Koch) moult to maturity in late spring, the males on average maturing before the females. In laboratory experiments, three environmental cues were manipulated―photoperiod, temperature and food level―to assess their ...
Bengt Gunnarsson, Jörgen Johnsson, Jorgen Johnsson   +2 more
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MATHEMATICAL MODELING OF POPULATION DYNAMICS WITH PROTANDRY

Informatika i sistemy upravleniya
A mathematical model of population dynamics with protandry and density-dependent birth rate regulation is proposed. An analytical and numerical study of the model is conducted. It is shown that regular, quasi-periodic and chaotic oscillations, as well as multistability, arise in the model, i.e. a change in the dynamics regime is possible.
A.A. GROMYKO, G.P. NEVEROVA
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Sperm Competition Cannot Eliminate Protandry

Journal of Theoretical Biology, 1996
Abstract Many butterfly species are protandrous, that is males emerge some time before the females. Models aiming to explain protandry generally assume that females mate only once, while males are capable of multiple matings. This assumption is not generally fulfilled, however.
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The emergence of insect protandry: a "natural" evolutionary computation application

Proceedings of 1997 IEEE International Conference on Evolutionary Computation (ICEC '97), 2002
When resources and their consumers have matching distributions in space or time, an ideal free distribution (IFD) is achieved, whereby each consumer receives the same amount of resource. In nature, both spatial and temporal IFDs are commonplace, with protandry in insects providing a popular textbook example of the latter.
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