Mating system and alternative male mating tactics in the grass goby Zosterisessor ophiocephalus (Teleostei: Gobiidae)

2000 ◽  
Vol 137 (5-6) ◽  
pp. 1041-1048 ◽  
Author(s):  
C. Mazzoldi ◽  
M. Scaggiante ◽  
E. Ambrosin ◽  
M. B. Rasotto
Author(s):  
Roberto Pastres ◽  
Fabio Pranovi ◽  
Simone Libralato ◽  
Stefano Malavasi ◽  
Patrizia Torricelli

The present study aims to apply a growth model to a species with a conditional reproductive strategy, the grass goby Zosterisessor ophiocephalus (Pisces: Gobiidae), in order to evaluate the adoption of alternative tactics by this species under the constraints of different dates of birth. The model describes the growth pattern (based on age, weight and gonadosomatic index data) of an individual, assumed to be representative of a given cohort, while also taking into account the energetic loss due to parental care. The most important parameters have been calibrated by comparing the results with a set of data collected in the lagoon of Venice. The comparison between the growth pattern of a parental male and that of a late-born male suggests that the birthday could be one of the major constraints affecting the adoption of an alternative tactic during the first breeding season.


2013 ◽  
Vol 280 (1755) ◽  
pp. 20122891 ◽  
Author(s):  
Lisa Locatello ◽  
Federica Poli ◽  
Maria B. Rasotto

Seminal fluid often makes up a large part of an ejaculate, yet most empirical and theoretical studies on sperm competition have focused on how sperm characteristics (number and quality) affect fertilization success. However, seminal fluid influences own sperm performance and may potentially influence the outcome of sperm competition, by also affecting that of rivals. As a consequence males may be expected to allocate their investment in both sperm and seminal fluid in relation to the potential level of competition. Grass goby ( Zosterisessor ophiocephalus ) is an external fertilizer with guard-sneaker mating tactics, where sperm competition risk varies according to the tactic adopted. Here, we experimentally manipulated grass goby ejaculates by separately combining sperm and seminal fluid from territorial and sneaker males. While sperm of sneaker and territorial males did not differ in their performance when they interacted with their own seminal fluid only, sperm of sneakers increased their velocity and fertilization rate in the presence of territorial males' seminal fluid. By contrast, sneaker males' seminal fluid had a detrimental effect on the performance of territorial males' sperm. Sperm velocity was unaffected by the seminal fluid of males employing the same tactic, suggesting that seminal fluid's effect on rival-tactic sperm is not based on a self/non-self recognition mechanism. Our findings show that cross interactions of sperm and seminal fluid may influence the fertilization success of competing ejaculates with males investing in both sperm and seminal fluid in response to sperm competition risk.


2005 ◽  
Vol 83 (12) ◽  
pp. 1638-1642 ◽  
Author(s):  
Albrecht I Schulte-Hostedde ◽  
Gary Burness

Sperm competition results in the evolution of ejaculate characteristics such as high sperm density, high motility, and fast sperm swimming speed. A fundamental assumption of sperm competition theory is that ejaculates with high motility and fast-swimming sperm have an advantage with respect to fertilization success. We tested this assumption by studying the fertilization dynamics of alternative mating tactics (cuckolders and parentals) of male bluegill (Lepomis macrochirus Rafinesque, 1819). Sneakers (cuckolders) have faster swimming sperm and a higher proportion of motile sperm immediately following sperm activation than do parentals; however, these variables decline more quickly over time in sneaker sperm than in the sperm of parental males. We used a controlled fertilization experiment to test the prediction that parental males will have higher fertilization success than sneakers late in the sperm activation cycle because of the reduced rate of decline in ejaculate quality over time. We found that as the time from sperm activation increases parental sperm fertilizes more eggs than the sperm of sneakers. Our results support the idea that fertilization success is higher when ejaculates contain a higher proportion of either motile sperm or faster swimming sperm, all else being equal. In addition, after controlling for time from sperm activation, we found a significant bias in fertilization success toward parental males, suggesting that cryptic female choice might play a role in fertilization dynamics.


2012 ◽  
Vol 153 (4) ◽  
pp. 999-1009 ◽  
Author(s):  
D. E. Chamberlain ◽  
M. Bocca ◽  
L. Migliore ◽  
E. Caprio ◽  
A. Rolando

2017 ◽  
Vol 233 (3) ◽  
pp. 219-226 ◽  
Author(s):  
Chun-Yen Lin ◽  
Chuan-Chin Chiao

1999 ◽  
Vol 66 (2) ◽  
pp. 125-139 ◽  
Author(s):  
Damijana Ota ◽  
Marco Francese ◽  
Enrico A. Ferrero

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