First observations of spawning nests in the pouched lamprey (Geotria australis)

The pouched lamprey (Geotria australis), one of four Southern Hemisphere lamprey species, is New Zealand’s only freshwater representative of the agnathans. In contrast to that of Northern Hemisphere lampreys, the reproductive ecology of Southern Hemisphere lampreys is poorly understood, with no documented nesting sites or spawning behaviours. In the present study, we utilized passive integrated transponder tags to track migratory adult G. australis to locate spawning sites. Across 2 years, six cryptic nesting sites were discovered, each containing eggs and a single male and female lamprey. The postspawning pairs were all located underneath large boulders, with the eggs forming a coagulated cluster that adhered to the underside of the boulder. Both the male and female lamprey survived spawning for over 105 days. The observed spawning nests highlight a substantial divergence in the reproductive behaviour between Northern and Southern Hemisphere lampreys, as the present observations of G. australis are the first that support clustered cryptic egg deposition and an extended time to mortality postspawning. This study offers the first insights to the long-standing mystery of Southern Hemisphere lamprey reproduction.

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VARIATION IN PACIFIC SALMON REPRODUCTIVE BEHAVIOUR ASSOCIATED WITH SPECIES, SEX AND LEVELS OF COMPETITION

Behaviour ◽

10.1163/156853999501270 ◽

1999 ◽

Vol 136 (2) ◽

pp. 179-204 ◽

Cited By ~ 32

Author(s):

Thomas Quinn

Keyword(s):

Pacific Salmon ◽

Local Area ◽

Reproductive Behaviour ◽

Male Aggression ◽

Male And Female ◽

Sexual Display ◽

Resource Space ◽

Intensity Of Competition ◽

Satellite Males ◽

Spawning Sites

AbstractMale and female Pacific salmon compete for different resources; females for suitable spawning sites and males for access to ripe females. Aggression should thus be primarily intra-sexual rather than inter-sexual. When different species are sympatric, males should primarily attack conspecifics whereas females should attack all females, regardless of species because they all compete for the same resource-space. The level of aggression should be a function of density, being relatively low at low densities and peaking at either intermediate or high densities. These predictions were supported in most respects by data collected on the behaviour of adult sockeye (Oncorhynchus nerka), chum (O. keta) and pink (O. gorbuscha) salmon in a large, relatively homogeneous spawning channel. Males almost exclusively attacked other males, especially conspecifics. Females were more likely to attack female heterospecifics than males but still tended to attack conspecifics most often, and also directed many attacks at males. Male aggression and digging, apparently a form of intra-sexual display, were related to density of male conspecifics in the local area, and the intensity of competition from satellite males courting the female.

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Male-biased sex ratio in Argulus canadensis Wilson, 1916 (Crustacea: Branchiura) ectoparasitic on sticklebacks

Canadian Journal of Zoology ◽

10.1139/z89-296 ◽

1989 ◽

Vol 67 (8) ◽

pp. 2078-2080 ◽

Cited By ~ 3

Author(s):

Robert Poulin ◽

Gerard J. FitzGerald

Keyword(s):

Salt Marsh ◽

Sex Ratio ◽

Laboratory Experiments ◽

Fish Predation ◽

Reproductive Behaviour ◽

Egg Deposition ◽

Alternative Hypotheses ◽

Biased Sex Ratio ◽

The Difference ◽

Fish Hosts

Females of the ectoparasitic crustacean Argulus canadensis must leave their fish hosts at least temporarily to deposit their eggs on the substrate. To test the hypothesis that this difference in reproductive behaviour between the two sexes could result in male-biased sex ratios on their stickleback hosts, we sampled sticklebacks in tide pools of a Quebec salt marsh from early July to early September 1986. During this period, fish harboured significantly more male than female A. canadensis. Laboratory experiments were done to test two alternative hypotheses offered to explain this biased sex ratio. The first hypothesis was that male A. canadensis were more successful than females in attacking their stickleback hosts; however, we found no differences in attack success on their hosts between the two parasite sexes. The second hypothesis was that sticklebacks ate more female than male A. canadensis. Although males were less vulnerable to fish predation than females, the difference was not significant. We conclude that sexual differences in reproductive behaviour, i.e., egg deposition behaviour of females, can account for the male-biased sex ratio of A. canadensis on sticklebacks.

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Evolutionary insight from a humble fly: sperm competition and the yellow dungfly

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0062 ◽

2020 ◽

Vol 375 (1813) ◽

pp. 20200062

Author(s):

Leigh W. Simmons ◽

Geoff A. Parker ◽

David J. Hosken

Keyword(s):

Sexual Selection ◽

Sperm Competition ◽

Paradigm Shift ◽

Mate Guarding ◽

Reproductive Behaviour ◽

Costs And Benefits ◽

Theme Issue ◽

Male And Female ◽

Sexual Selection Theory ◽

The 1960S

Studies of the yellow dungfly in the 1960s provided one of the first quantitative demonstrations of the costs and benefits associated with male and female reproductive behaviour. These studies advanced appreciation of sexual selection as a significant evolutionary mechanism and contributed to the 1970s paradigm shift toward individual selectionist thinking. Three behaviours in particular led to the realization that sexual selection can continue during and after mating: (i) female receptivity to remating, (ii) sperm displacement and (iii) post-copulatory mate guarding. These behaviours either generate, or are adaptations to sperm competition, cryptic female choice and sexual conflict. Here we review this body of work, and its contribution to the development of post-copulatory sexual selection theory. This article is part of the theme issue ‘Fifty years of sperm competition’.

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Redescription of the Central American genus Moribaetis Waltz & McCafferty 1985 (Ephemeroptera, Baetidae)

Zootaxa ◽

10.11646/zootaxa.4521.2.5 ◽

2018 ◽

Vol 4521 (2) ◽

pp. 231

Author(s):

NIKITA J. KLUGE ◽

JUAN A. BERNAL VEGA

Keyword(s):

New Species ◽

Costa Rica ◽

Type Species ◽

Central American ◽

Type Locality ◽

New Combination ◽

Single Male ◽

Male And Female ◽

A New Species

A new definition for the genus Moribaetis Waltz & McCafferty 1985 is given. Its type species, Moribaetis maculipennis (Flowers 1979) is redescribed based on male and female imagoes reared from larvae near the type locality in Panama. Larvae, formerly wrongly attributed to Moribaetis salvini (Eaton 1885), and a male imago, formerly wrongly attributed to Moribaetis macaferti Waltz 1985, belong to a new species Moribaetis latipennis sp. n., which is described here based on a male imago reared from larva in Panama. Both species, M. maculipennis and M. latipennis sp. n., are distinct from M. salvini, which is known as a single male imago (lectotype) from Costa Rica. All other species, formerly attributed to Moribaetis, are excluded from this genus; a new combination Caribaetis macaferti comb. n. is proposed for the species originally described as Moribaetis macaferti Waltz (in Waltz & McCafferty) 1985, and a new combination Baetis (Rhodobaetis) mimbresaurus comb. n. is proposed for the species originally described as Moribaetis mimbresaurus McCafferty 2007.

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Low sperm to egg ratio required for successful in vitro fertilisation in a pair-spawning teleost, Senegalese sole (Solea senegalensis)

10.1101/2020.08.26.267740 ◽

2020 ◽

Author(s):

Sandra Ramos-Júdez ◽

Wendy Ángela González-López ◽

Jhons Huayanay Ostos ◽

Noemí Cota Mamani ◽

Carlos Marrero Alemán ◽

...

Keyword(s):

Large Scale ◽

Reproductive Behaviour ◽

Poor Quality ◽

Solea Senegalensis ◽

In Vitro Fertilisation ◽

Hatching Rate ◽

Senegalese Sole ◽

Single Male ◽

Close Proximity

AbstractCultured Senegalese sole (Solea senegalensis) breeders fail to spawn fertilised eggs and this bottleneck could be solved with the implementation of large-scale in vitro fertilisation protocols. However, low production of poor-quality sperm has frustrated the development of in vitro fertilisation protocols. Cultured females were induced to ovulate with a 5 µg kg-1 single injection of gonadotropin releasing hormone agonist (GnRHa) and good quality eggs (82.6 ± 9.2% fertilisation) were stripped 41:57 ± 1:46 h after the injection. Sperm was collected from cultured males, diluted in modified Leibovitz and used fresh to fertilise the eggs. A non-linear regression, an exponential rise to a maximum (R = 0.93, P < 0.0001) described the number of motile spermatozoa required to fertilise a viable egg and 1617 motile spermatozoa were sufficient to fertilise 99 ± 12% (± 95% CI) of viable eggs. Similar, spermatozoa egg-1 ratios of 592 ± 611 motile spermatozoa egg-1 were used in large-scale in vitro fertilisations with 190,512 ± 38,471 eggs. The sperm from a single male (145 ± 50 µL or 8.0 ± 6.8 × 108 spermatozoa) was used to fertilise the eggs. The mean hatching rate of the large-scale in vitro fertilisations was 70 ± 14 % to provide 131,540 ± 34,448 larvae per fertilisation. When unfertilised eggs were stored at room temperature the percentage of viable eggs decreased gradually and indicated the sooner eggs were fertilised after stripping the higher the viability of the eggs. The collection of sperm directly into a syringe containing modified Leibovitz significantly increased the percentage of motile spermatozoa (33.4 ± 12.2 %) compared to dilution in modified Leibovitz immediately after collection (6.6 ± 4.9 %). Senegalese sole have a pair-spawning reproductive behaviour characterised by external gamete fertilisation in close proximity with no sperm competition. The low spermatozoa egg-1 ratio required for maximum fertilisation was consistent with this reproductive behaviour and strategy. The provision of a large-scale in vitro fertilisation protocol (200 µL of sperm per 100 mL of eggs) will enable the industry to operate sustainably and implement breeding programs to improve production.

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Changes in serum concentrations of steroids during embryonic and post-hatching development of male and female Japanese quail (Coturnix coturnix japonica)

Journal of Endocrinology ◽

10.1677/joe.0.1180127 ◽

1988 ◽

Vol 118 (1) ◽

pp. 127-134 ◽

Cited By ~ 49

Author(s):

M. Schumacher ◽

J. Sulon ◽

J. Balthazart

Keyword(s):

Japanese Quail ◽

Reproductive Behaviour ◽

Coturnix Japonica ◽

Coturnix Coturnix Japonica ◽

Serum Concentrations ◽

Male And Female ◽

Coturnix Coturnix ◽

Hatching Time ◽

Embryonic Life ◽

Age Range

ABSTRACT Serum concentrations of testosterone, 5α-dihydrotestosterone, oestradiol and progesterone were measured by radioimmunoassay combined with Celite chromatography in male and female Japanese quail (Coturnix coturnix japonica) during the second half of embryonic life (days 9–17 of incubation) and during the first 5 weeks after hatching. The mean level of each of the four steroids was significantly affected by the age of the birds. An overall effect of sex was detected by analysis of variance only on oestradiol concentrations, with females having higher serum concentrations than males during most of the age range studied. Significant peaks of testosterone and progesterone were also detected around hatching time. These results are consistent with the view that oestradiol is the major hormone implicated in the sexual differentiation of reproductive behaviour in the quail. The relationships between the circulating concentrations of oestradiol during ontogeny and the critical period of differentiation as postulated by currently accepted models is also discussed. J. Endocr. (1988) 118, 127–134

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