Is sperm viability independent of ejaculate size in the house cricket (Acheta domesticus)?

2011 ◽  
Vol 89 (12) ◽  
pp. 1231-1236 ◽  
Author(s):  
Brian E. Gress ◽  
Clint D. Kelly
Keyword(s):  
Experimental Treatment ◽  
Acheta Domesticus ◽  
Sperm Viability ◽  
Sperm Number ◽  
Physical Damage ◽  
Viability Assay ◽  
Ejaculate Size ◽  
Sperm Counts ◽  
Spurious Results ◽  
Related Mortality

Assessing sperm viability is a popular means of testing hypotheses related to ejaculate quality. This technique has produced interesting results; however, the sperm viability assay itself may kill sperm. This is a serious pitfall, as assay-related mortality could confound results and produce artificially low estimates of viability. To avoid spurious results, it has been recommended that investigators include sperm number in their viability analyses. Unfortunately, studies conducted to date on internal fertilizers have not included sperm counts in their analyses, so it is not possible to assess whether this factor can indeed produce artefactual results. In this paper, we use male house crickets ( Acheta domesticus (L., 1758)) to show that sperm viability is dependent on sperm number and exclusion of this factor from statistical analyses affects our interpretation of experimental treatment results. We show that mechanically rupturing a spermatophore significantly reduces sperm viability, but this does not appear to drive the nonindependent relationship between viability and number. Instead, our study shows that nonindependence is due to processes other than differential physical damage to the sperm during collection. We also show that allowing a spermatophore to evacuate its sperm without rupturing for 10 min maximizes both sperm number and viability.

scholarly journals Influence of Sperm Number Per Straw on the Post-Thaw Sperm Viability and Fertility of Swedish Red and White A.I. Bulls

1996 ◽  
Vol 37 (4) ◽  
pp. 461-470
Author(s):  
A. Januskauskas ◽  
L. Söderquist ◽  
M. G. Håård ◽  
M. Ch ◽  
N. Lundeheim ◽  
...  
Keyword(s):  
Sperm Viability ◽  
Sperm Number

scholarly journals Apis mellifera (Hymenoptera: Apidae) drone sperm quality in relation to age, genetic line, and time of breeding

2015 ◽  
Vol 147 (6) ◽  
pp. 702-711 ◽  
Author(s):  
Andrée Rousseau ◽  
Valérie Fournier ◽  
Pierre Giovenazzo
Keyword(s):  
Apis Mellifera ◽  
Honey Bee ◽  
Sperm Quality ◽  
Research Centre ◽  
Sperm Viability ◽  
Sperm Number ◽  
Genetic Line ◽  
Semen Volume ◽  
Time Of Breeding ◽  
Honey Bee Queen

AbstractA honey bee (Apis mellifera Linnaeus; Hymenoptera: Apidae) queen’s life expectancy is strongly dependent on the number of sperm she obtains by mating with drones during nuptial flights. Unexplained replacement of queens by the colony and young queens showing sperm depletions have been reported in North America, and reduced drone fertility has been a suspected cause. The aim of this study was to evaluate drone reproductive qualities during the queen-rearing season, from May to August. Drones from two different genetic lines were reared six times during the 2012 beekeeping season at our research centre in Québec (Canada). Semen volume as well as sperm number and viability were assessed at the ages of 14, 21, and 35 days. Results showed (1) a greater proportion of older drones with semen at the tip of the genitalia after eversion; (2) an influence of rearing date on semen production; and (3) no influence of drone genetic line, age or time of breeding on sperm viability. These results highlight the necessity of better understanding drone rearing and how it can be improved to ensure optimum honey-bee queen mating.

scholarly journals Larger testes are associated with a higher level of polyandry, but a smaller ejaculate volume, across bushcricket species (Tettigoniidae)

2010 ◽  
Vol 7 (2) ◽  
pp. 261-264 ◽  
Author(s):  
Karim Vahed ◽  
Darren J. Parker ◽  
James D. J. Gilbert
Keyword(s):  
Sperm Competition ◽  
Male Mating ◽  
Intensity Increase ◽  
Nuptial Gift ◽  
Sperm Number ◽  
Competition Intensity ◽  
Confounding Effect ◽  
Ejaculate Size ◽  
Testes Size ◽  
Testis Mass

While early models of ejaculate allocation predicted that both relative testes and ejaculate size should increase with sperm competition intensity across species, recent models predict that ejaculate size may actually decrease as testes size and sperm competition intensity increase, owing to the confounding effect of potential male mating rate. A recent study demonstrated that ejaculate volume decreased in relation to increased polyandry across bushcricket species, but testes mass was not measured. Here, we recorded testis mass for 21 bushcricket species, while ejaculate (ampulla) mass, nuptial gift mass, sperm number and polyandry data were largely obtained from the literature. Using phylogenetic-comparative analyses, we found that testis mass increased with the degree of polyandry, but decreased with increasing ejaculate mass. We found no significant relationship between testis mass and either sperm number or nuptial gift mass. While these results are consistent with recent models of ejaculate allocation, they could alternatively be driven by substances in the ejaculate that affect the degree of polyandry and/or by a trade-off between resources spent on testes mass versus non-sperm components of the ejaculate.

scholarly journals Protein and carbohydrate intake influence sperm number and fertility in male cockroaches, but not sperm viability

2015 ◽  
Vol 282 (1802) ◽  
pp. 20142144 ◽  
Author(s):  
Harriet Bunning ◽  
James Rapkin ◽  
Laurence Belcher ◽  
C. Ruth Archer ◽  
Kim Jensen ◽  
...  
Keyword(s):  
Recent Work ◽  
Male Fertility ◽  
Nutrient Intake ◽  
Sperm Viability ◽  
Sperm Number ◽  
Sperm Production ◽  
High Intake ◽  
Trade Off ◽  
Numerous Species ◽  
Dietary Choice

It is commonly assumed that because males produce many, tiny sperm, they are cheap to produce. Recent work, however, suggests that sperm production is not cost-free. If sperm are costly to produce, sperm number and/or viability should be influenced by diet, and this has been documented in numerous species. Yet few studies have examined the exact nutrients responsible for mediating these effects. Here, we quantify the effects of protein (P) and carbohydrate (C) intake on sperm number and viability in the cockroach Nauphoeta cinerea , as well as the consequences for male fertility. We found the intake of P and C influenced sperm number, being maximized at a high intake of diets with a P : C ratio of 1 : 2, but not sperm viability. The nutritional landscapes for male fertility and sperm number were closely aligned, suggesting that sperm number is the major determinant of male fertility in N. cinerea . Under dietary choice, males regulate nutrient intake at a P : C ratio of 1 : 4.95, which is midway between the ratios needed to maximize sperm production and pre-copulatory attractiveness in this species. This raises the possibility that males regulate nutrient intake to balance the trade-off between pre- and post-copulatory traits in this species.

Electron investigations of rhabdovirus-like particles in mexican bean beetles and crickets

1978 ◽  
Vol 36 (2) ◽  
pp. 378-379
Author(s):  
J. R. Adams ◽  
G. J Tompkins ◽  
A. M. Heimpel ◽  
E. Dougherty
Keyword(s):  
Biological Control ◽  
Integrated Pest Management ◽  
Pest Management ◽  
Developmental Stages ◽  
Management Program ◽  
Acheta Domesticus ◽  
Epilachna Varivestis ◽  
House Cricket ◽  
Similar Morphology ◽  
Bean Beetle

As part of a continual search for potential pathogens of insects for use in biological control or on an integrated pest management program, two bacilliform virus-like particles (VLP) of similar morphology have been found in the Mexican bean beetle Epilachna varivestis Mulsant and the house cricket, Acheta domesticus (L. ).Tissues of diseased larvae and adults of E. varivestis and all developmental stages of A. domesticus were fixed according to procedures previously described. While the bean beetles displayed no external symptoms, the diseased crickets displayed a twitching and shaking of the metathoracic legs and a lowered rate of activity.Examinations of larvae and adult Mexican bean beetles collected in the field in 1976 and 1977 in Maryland and field collected specimens brought into the lab in the fall and reared through several generations revealed that specimens from each collection contained vesicles in the cytoplasm of the midgut filled with hundreds of these VLP's which were enveloped and measured approximately 16-25 nm x 55-110 nm, the shorter VLP's generally having the greater width (Fig. 1).

A technique for protecting delicate specimens during processing

1989 ◽  
Vol 47 ◽  
pp. 982-983
Author(s):  
R.J. Mount ◽  
R.V. Harrison
Keyword(s):  
Basilar Membrane ◽  
Low Cost ◽  
Organ Of Corti ◽  
Region Of Interest ◽  
Sensory Epithelium ◽  
Physical Damage ◽  
Air Drying ◽  
Specimen Handling ◽  
Two Component

The sensory end organ of the ear, the organ of Corti, rests on a thin basilar membrane which lies between the bone of the central modiolus and the bony wall of the cochlea. In vivo, the organ of Corti is protected by the bony wall which totally surrounds it. In order to examine the sensory epithelium by scanning electron microscopy it is necessary to dissect away the protective bone and expose the region of interest (Fig. 1). This leaves the fragile organ of Corti susceptible to physical damage during subsequent handling. In our laboratory cochlear specimens, after dissection, are routinely prepared by the O-T- O-T-O technique, critical point dried and then lightly sputter coated with gold. This processing involves considerable specimen handling including several hours on a rotator during which the organ of Corti is at risk of being physically damaged. The following procedure uses low cost, readily available materials to hold the specimen during processing ,preventing physical damage while allowing an unhindered exchange of fluids.Following fixation, the cochlea is dehydrated to 70% ethanol then dissected under ethanol to prevent air drying. The holder is prepared by punching a hole in the flexible snap cap of a Wheaton vial with a paper hole punch. A small amount of two component epoxy putty is well mixed then pushed through the hole in the cap. The putty on the inner cap is formed into a “cup” to hold the specimen (Fig. 2), the putty on the outside is smoothed into a “button” to give good attachment even when the cap is flexed during handling (Fig. 3). The cap is submerged in the 70% ethanol, the bone at the base of the cochlea is seated into the cup and the sides of the cup squeezed with forceps to grip it (Fig.4). Several types of epoxy putty have been tried, most are either soluble in ethanol to some degree or do not set in ethanol. The only putty we find successful is “DUROtm MASTERMENDtm Epoxy Extra Strength Ribbon” (Loctite Corp., Cleveland, Ohio), this is a blue and yellow ribbon which is kneaded to form a green putty, it is available at many hardware stores.

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