Factors influencing the degree of sexual size dimorphism within and among calanoid copepod species

Nishikawa, Timothy S.; Maly, Edward J.

doi:10.1007/bf00333940

Cited by 6 publications

(4 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A few studies on SSD have explicitly focused on inter‐ and intraspecific variation at a time (Nishikawa & Maly, ), and some evidence can be derived from studies on body size variation (Shelomi, ). Nevertheless, combining analyses of inter‐ and intraspecific variation in SSD within the same evolutionary and climatic scenarios may serve to contrast the effects of the climate on different underlying mechanisms, mainly evolutionary or macroevolutionary (among species or higher taxa) and ontogenetic or microevolutionary (within species or populations; Simmons, ).…”

Section: Introductionmentioning

confidence: 99%

Local climate determines intra‐ and interspecific variation in sexual size dimorphism in mountain grasshopper communities

Laiolo

Illera

Obeso

2013

J of Evolutionary Biology

View full text Add to dashboard Cite

The climate is often evoked to explain broad-scale clines of body size, yet its involvement in the processes that generate size inequality in the two sexes (sexual size dimorphism) remains elusive. Here, we analyse climatic clines of sexual size dimorphism along a wide elevation gradient (i) among grasshopper species in a phylogenetically controlled scenario and (ii) within species differing in distribution and cold tolerance, to highlight patterns generated at different time scales, mainly evolutionary (among species or higher taxa) and ontogenetic or microevolutionary (within species). At the interspecific level, grasshoppers were slightly smaller and less dimorphic at high elevations. These clines were associated with gradients of precipitation and sun exposure, which are likely indicators of other factors that directly exert selective pressures, such as resource availability and conditions for effective thermoregulation. Within species, we found a positive effect of temperature and a negative effect of elevation on body size, especially on condition-dependent measures of body size (total body length rather than hind femur length) and in species inhabiting the highest elevations. In spite of a certain degree of species-specific variation, females tended to adjust their body size more often than males, suggesting that body size in females can evolve faster among species and can be more plastic or dependent on nutritional conditions within species living in adverse climates. Natural selection on female body size may therefore prevail over sexual selection on male body size in alpine environments, and abiotic factors may trigger consistent phenotypic patterns across taxonomic scales.

show abstract

Section: Introductionmentioning

confidence: 99%

Local climate determines intra‐ and interspecific variation in sexual size dimorphism in mountain grasshopper communities

Laiolo

Illera

Obeso

2013

J of Evolutionary Biology

View full text Add to dashboard Cite

show abstract

“…The higher relative size of female copepods has been hypothesised to be due to the greater investment in reproduction and offspring in the female, particularly in the species that carry the eggs during their development (Gilbert & Williamson 1983). Large females are more fecund (Cole 1966;Corkett & McLaren 1969;Hopkins 1977;Maly 1983), but they may reach maturity slower than small females or males (Gilbert & Williamson 1983;Nishikawa & Maly 1996). Some females store most of the energy for reproduction during their development, so the adult final size represents the maximum potential resource base that can be put towards reproduction (Gilbert & Williamson 1983).…”

Section: Introductionmentioning

confidence: 99%

Sexual size dimorphism in calanoid copepods (Centropagidae) from Patagonia (Argentina)

Garcia

Reissig

2013

New Zealand Journal of Marine and Freshwater Research

View full text Add to dashboard Cite

Calanoid copepods of the genus Boeckella and Parabroteas (P. sarsi) are dominant in zooplankton communities of Patagonian lakes and ponds. This study addresses the occurrence of sexual size dimorphism in calanoid copepods of the genus Boeckella and in the monospecific genus Parabroteas occurring in 12 lakes and ponds of Patagonia (Argentina). The morphometric analysis performed showed that in all the species studied the female is larger than the male, although the difference in size among sexes was found to be variable between species. Interestingly, all species showed significant intraspecific stability in their sexual size dimorphism despite potential differences in their environments regarding predation pressure, environmental stability (permanent or temporary waters) and altitude distribution of populations. Finally, we discuss the potential implications of sexual dimorphism in terms of resource use and vulnerability to predation among other environmental forces which may play a role in promoting larger female to male size.

show abstract

“…Consequently, one way of increasing copepod performances in aquaculture can be the selection of large females. It is known that large copepod females are more fecund, but may mature more slowly than small females or males (Gilbert & Williamson ; Nishikawa & Maly ). For aquaculture purposes, it is important to select fast growing females with high fecundity.…”

Section: Discussionmentioning

confidence: 99%

Physiological improvement in the copepodEurytemora affinisthrough thermal and multi-generational selection

Souissi

Hansen

2014

Aquac Res

View full text Add to dashboard Cite

As a major part of fish larval diet in nature, copepods constitute an appropriate live prey for aquaculture purposes. Considering the difficulty of mastering copepod mass production, studies on their growth performance at different environmental conditions are needed to improve their productivity. In this study a new selective approach based on temperature control is proposed to improve the physiological (body size, fecundity and lipid storage) performance of copepods. The estuarine copepod Eurytemora affinis known to have a high genetic variance in temperature tolerance was used as a biological model. First two different copepod lines were obtained after long-term culture at constant cold (7°C) and warm (20°C) temperatures. Then both populations were transferred to a higher temperature of 24°C appropriate for aquaculture use and followed during five generations. During the first two generations (F1-F2) of a cold-acclimated population, female body size and fecundity decreased significantly whereas the survival rate remained high. The high lipid content of this population was used by females to compensate the heat shock of more than 10°C. However, the survival rate decreased dramatically in F3 but allowed the selection of robust individuals which progressively improved their fitness during the following generations. So, compared to the warm acclimated population, the cold acclimated one showed larger body size, higher fecundity and better lipid storage. After only five generations at 24°C the cold-acclimated population showed a significant genetic gain in prosome length compared to the warm acclimated one.

show abstract

Factors influencing the degree of sexual size dimorphism within and among calanoid copepod species

Cited by 6 publications

References 31 publications

Local climate determines intra‐ and interspecific variation in sexual size dimorphism in mountain grasshopper communities

Local climate determines intra‐ and interspecific variation in sexual size dimorphism in mountain grasshopper communities

Sexual size dimorphism in calanoid copepods (Centropagidae) from Patagonia (Argentina)

Physiological improvement in the copepodEurytemora affinisthrough thermal and multi-generational selection

Contact Info

Product

Resources

About