Effects of constant and fluctuating temperatures on egg production in the threespine stickleback (Gasterosteus aculeatus)

1989 ◽  
Vol 67 (6) ◽  
pp. 1599-1602 ◽  
Author(s):  
Vital Boulé ◽  
Gerard J. Fitzgerald

Female threespine sticklebacks (Gasterosteus aculeatus) spend only 9–15 days on the spawning grounds, an intertidal salt marsh at Isle Verte, Quebec, during a 2-month breeding season. Individuals average only one spawning. However, in the laboratory they lay clutches of several hundred eggs every 3–5 days for several months. We designed laboratory experiments to determine (i) whether daily temperature fluctuations similar to those encountered in the marsh affect reproduction (number of clutches, number of eggs per clutch, and size of eggs) and (ii) whether the amplitude of the fluctuations encountered by the fish affects reproduction. We compared the reproduction of females held in fluctuating temperatures with that of females kept at 20 °C. Fish kept under fluctuating conditions produced more eggs per clutch but had longer interspawning intervals than those at 20 °C. Total seasonal egg production and egg size did not differ between the two groups. Fish in fluctuating temperatures survived longer and were in better condition than those at 20 °C. We conclude that the amplitude of the fluctuations is less important than mean temperature in determining reproductive performance. Fluctuating temperatures on the spawning grounds are not responsible for the short residency there.

1995 ◽  
Vol 73 (11) ◽  
pp. 2154-2158 ◽  
Author(s):  
Rees Kassen ◽  
Dolph Schluter ◽  
John Donald McPhail

Geologic and allozyme evidence suggests that threespine sticklebacks (Gasterosteus aculeatus complex) in low-lying southwestern British Columbia lakes were founded during two incursions of marine sticklebacks after the retreat of the Pleistocene glaciers (the double-invasion hypothesis). We used the salinity tolerance of embryos, measured as hatchability in salt water, to establish the relative order of freshwater invasion by marine sticklebacks and to test the double-invasion hypothesis. Limnetics and an anadromous population hatched nearly equivalent numbers of young in salt water as in fresh water, whereas benthics and one solitary freshwater population had low hatchability in salt water. We also found that eggs from freshwater populations were larger than those from marine populations and limnetics had smaller eggs than benthics and the solitary population. These results support the double-invasion hypothesis and suggest a trend of increasing egg size with increasing time spent in fresh water.


Parasitology ◽  
2015 ◽  
Vol 142 (12) ◽  
pp. 1535-1542 ◽  
Author(s):  
IRINA S. KHOKHLOVA ◽  
ELIZABETH M. DLUGOSZ ◽  
BORIS R. KRASNOV

SUMMARYTo understand mechanisms behind positive interspecific co-occurrences in flea infracommunities, we asked whether co-infestation results in an increase of flea fitness (quantity and/or quality of the offspring). We studied reproductive performance of Xenopsylla ramesis and Parapulex chephrenis when they exploited their characteristic host (Meriones crassus and Acomys cahirinus, respectively) either alone or together with another species. We used egg production, the number of new imagoes, pre-imaginal survival and egg size as fitness-related variables and predicted that fitness will be higher in fleas feeding in mixed- than in single-species groups. In both fleas, mean number of eggs produced per female flea did not depend on experimental treatment. No effect of single- vs mixed-species infestation on the mean number of new imagoes per female and the number of emerged imagoes per egg was found for X. ramesis, whereas both these numbers were higher in mixed- than in single-species groups for P. chephrenis. X. ramesis produced eggs of similar size independently of treatment, whereas eggs produced by P. chephrenis in mixed-species groups were significantly larger than eggs produced in single-species groups. We conclude that an increase in reproductive performance as a response to co-infestation may be one of the mechanisms behind aggregative structure of flea infracommunities. However, this response may vary among flea species.


1990 ◽  
Vol 68 (9) ◽  
pp. 2027-2030 ◽  
Author(s):  
Randal J. Snyder

There is conflicting evidence in the literature regarding the size-specific fecundity of anadromous and freshwater threespine sticklebacks (Gasterosteus aculeatus L.). To examine this question, I reared offspring of threespine sticklebacks collected from an inland location along the Navarro River, Mendocino County, California, and compared their initial clutch size and egg size with data obtained earlier for two other stickleback populations (an anadromous and a coastal freshwater population) from the same drainage. Size-specific clutch size was lower and eggs were larger in the inland population compared with the two populations studied previously. When wild-caught threespine sticklebacks are compared, fecundity of anadromous forms should usually be higher due to their higher size-specific fecundity as well as their larger average size at maturity. The eggs of anadromous sticklebacks may also be smaller than those of typical freshwater sticklebacks, since there is evidence of negative phenotypic correlations between egg size and clutch size in these fish.


Intermittent Lighting Improves the Efficiency of Artificial Insemination in Cage Housed Laying Hens Kavtarashvili A.Sh., Kolokolnikova T.N. Federal Scientific Center “All-Russian Research and Technological Poultry Institute” of Russian Academy of Sciences Omsk Agrarian Scientific Center Summary: The effects of different lighting regimes on the oviposition schedule, productive performance, and reproductive efficiency in cage housed laying hens of layer parental flock (Hisex White-R) were studied; the reasonable regime of artificial insemination (AI) under intermittent lighting is proposed. It was found that intermittent lighting regime 1L:4D:4L:1D:4L:10D compared to the constant lighting significantly alters oviposition schedule: under this regime 82.3% of all daily eggs were laid until 9 am (vs. 66.6% in control). This regime and AI at 10 am improved the productive and reproductive performance compared to control (constant lighting 16L:8D and AI at 12 am): mortality by 1.9%, egg production per initial hen by 3.8%, egg weight by 1.1%, percentage of eggs suitable for incubation by 1.9%, egg fertility by 0.9%, hatchability by 2.3%, hatch of chicks by 2.9%, feed conversion ratio (kg of feed per 10 eggs) by 5.3%, the expenses of electric energy for lighting (per 1000 eggs suitable for incubation) by 54.5%. Key words: INTERMITTENT LIGHTING, CAGE HOUSED LAYERS, ARTIFICIAL INSEMINATION (AI), OVIPOSITION SCHEDULE, AI TIMING, PRODUCTIVE PERFORMANCE, REPRODUCTIVE PERFORMANCE


Zoomorphology ◽  
2020 ◽  
Author(s):  
Harald Ahnelt ◽  
David Ramler ◽  
Maria Ø. Madsen ◽  
Lasse F. Jensen ◽  
Sonja Windhager

AbstractThe mechanosensory lateral line of fishes is a flow sensing system and supports a number of behaviors, e.g. prey detection, schooling or position holding in water currents. Differences in the neuromast pattern of this sensory system reflect adaptation to divergent ecological constraints. The threespine stickleback, Gasterosteus aculeatus, is known for its ecological plasticity resulting in three major ecotypes, a marine type, a migrating anadromous type and a resident freshwater type. We provide the first comparative study of the pattern of the head lateral line system of North Sea populations representing these three ecotypes including a brackish spawning population. We found no distinct difference in the pattern of the head lateral line system between the three ecotypes but significant differences in neuromast numbers. The anadromous and the brackish populations had distinctly less neuromasts than their freshwater and marine conspecifics. This difference in neuromast number between marine and anadromous threespine stickleback points to differences in swimming behavior. We also found sexual dimorphism in neuromast number with males having more neuromasts than females in the anadromous, brackish and the freshwater populations. But no such dimorphism occurred in the marine population. Our results suggest that the head lateral line of the three ecotypes is under divergent hydrodynamic constraints. Additionally, sexual dimorphism points to divergent niche partitioning of males and females in the anadromous and freshwater but not in the marine populations. Our findings imply careful sampling as an important prerequisite to discern especially between anadromous and marine threespine sticklebacks.


Author(s):  
S.-H. Kim ◽  
H. Park ◽  
W. Kim ◽  
J.-H. Song ◽  
S.J. Roh ◽  
...  

The establishment of efficient and sustainable production of industrially important insects necessitates the detailed knowledge of the optimal mixture of macronutrients required for maximising their performance and fitness. The white spotted flower chafer, Protaetia brevitarsis (Coleoptera: Scarabaeidae: Cetoniinae), is one of the most important edible insects in East Asia with high nutritional and medicinal value. Here, we report how the ratio of protein to digestible carbohydrate (P:C) in the diet influenced lifespan and reproductive performance in the adults of P. brevitarsis. Throughout their lifespan, beetles were fed ad libitum one of five diets with differing P:C ratio (0:1, 3:7, 1:1, 7:3, 1:0). Both lifespan and the number of eggs produced over the lifetime were maximised at the P:C ratio of 3:7 and declined as the ratio deviated away from this optimal P:C composition. Beetles fed a diet containing only protein (P:C 1:0) not only had the shortest lifespan but also exhibited substantially reduced lifetime egg production compared to those fed the other diets. However, the effects of dietary P:C ratio on daily egg production rate and egg hatchability were marginal. The number of eggs produced at each age stage peaked at the age of week 2 and then gradually declined with increasing age, showing the sign of reproductive senescence. Age-specific egg production was higher in beetles confined to three intermediate P:C ratios (3:7, 1:1, 7:3) than those confined to two extreme P:C ratios (0:1, 1:0) throughout their lifespan. The speed of age-related decrease in reproductive performance was the slowest at P:C 3:7. Our data have implications for optimising the production of this edible insect with emerging economic importance.


1998 ◽  
Vol 76 (4) ◽  
pp. 680-688 ◽  
Author(s):  
Christophe Garenc ◽  
Frederick G Silversides ◽  
Helga Guderley

Full-sib heritabilities of burst-swimming capacity and its enzymatic correlates were calculated in juvenile threespine sticklebacks, Gasterosteus aculeatus, from 25 families raised under constant laboratory conditions. Variation among families in burst-swimming performance, enzyme activities, body size, and condition of the juveniles was considerable. Estimates of full-sib heritabilities of absolute and relative burst-swimming performance decreased during ontogenesis, as they were higher for 2-month-old than for 3.6-month-old sticklebacks. This decline may reflect a decrease in the importance of paternal effects with age, as well as an increase in intrafamilial variability due to the existence of feeding or social hierarachies. Enzymatic correlates of burst-swimming performance measured in 3.6-month-old sticklebacks had higher full-sib heritabilities than burst-swimming performance itself, with the highest values found for cytochrome c oxidase, followed by lactate dehydrogenase and then phosphofructokinase and creatine phosphokinase. These results suggest that genetic factors may have a considerable influence upon burst-swimming performance and muscle metabolic capacities of juvenile threespine sticklebacks, but that this influence may be tempered by biotic interactions.


1989 ◽  
Vol 69 (3) ◽  
pp. 757-764 ◽  
Author(s):  
S. LEESON ◽  
L. J. CASTON ◽  
J. D. SUMMERS

Three experiments were undertaken to investigate the coccidiostat, nicarbazin, on reproductive performance of layers. In trial 1, levels of 0, 5, 10, 20, 40, 80, 125, and 200 ppm nicarbazin were fed to White leghorn laying hens for 5 wk. By the 2nd week of nicarbazin treatment, egg production was significantly reduced in birds fed 125 and 200 ppm (P < 0.05). Similarly, increasing levels of nicarbazin resulted in decreasing egg weights (P < 0.01) and feed intake was significantly decreased. However, by the 2nd week post-nicarbazin treatment, egg production, egg weight, and feed intake had returned to normal. Nicarbazin had no effect on egg shell deformation or body weight. Nicarbazin had a marked effect on hatchability; levels of 125 and 200 ppm reduced hatchability significantly (P < 0.01) as well as producing an increased incidence of malpositions and malformations. When nicarbazin was withdrawn from the diet, hatchability returned to pretreatment values although malpositions and malformations were still in evidence. Experiments 2 and 3 were designed to study the effect of nicarbazin on production of brown-shelled eggs. In the 2nd experiment 0, 5, 10, 20, and 40 ppm of dietary nicarbazin resulted in significant loss of shell color at 20 and 40 ppm, whereas in exp. 3 with levels of 0, 80, 125, and 200 ppm, brown eggs lost virtually all their color. It is concluded that the adult White Leghorn bird can tolerate up to 125 ppm nicarbazin without significant (P < 0.01) loss of reproductive performance although lower levels show a trend for reduced production. Hatchability is depressed with nicarbazin levels in excess of 80 ppm, while trace levels will produce a visual loss of color in brown-shelled eggs. Key words: Layer, coccidiostat, reproductive performance


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