Variation of Postembryonic Development Time and Number of Nymphal Instars on a Small Spatial Scale in Central European Grasshoppers  (Caelifera: Acrididae)

Schädler, Martin; Witsack, Werner

doi:10.1127/entom.gen/24/1999/125

Cited by 8 publications

(5 citation statements)

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“…Table I. monthly temperatures than those in the south (Curitiba, Carrasco) (Figure 1; Adis et al, 2004), and less pronounced winters. This influence would appear to agree with that reported in previous studies (Roff, 1992;Schädler & Witsack, 1999), where season length and development time (via female body size) have both been shown to influence growth function/patterns in grasshoppers. In addition, Roff (1980) has shown that at a certain point an increase in these variables makes it physically possible, and reproductively advantageous, to reduce the development time of single univoltine Table I. nymphs (so reducing the number of instar stages), and allow a second nymph to be produced within a seasonal environment (bivoltinism).…”

Section: Historical Structure and The Influence Of Current Climatic Vsupporting

confidence: 89%

What is responsible for the variance in life history traits of a South American semi‐aquatic grasshopper (Cornops aquaticum)? A test of three possible hypotheses

Brede

Adis

Schneider

2007

Studies on Neotropical Fauna and Environment

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The semi-aquatic grasshopper Cornops aquaticum (Bruner, 1906) is native to South America, with a distribution from the Argentinian pampas to the Gulf of Mexico, and is currently being proposed as a biological control agent for the invasive water hyacinth (Eichhornia crassipes) in South Africa. This study reports results of a neutral molecular marker (microsatellites) study on C. aquaticum within its native range. The data were analysed for levels of diversity and structure within/between South American populations, and correlations between host plant, geography and environmental/climatic variables were investigated. We found no evidence to support associations between host plant use and microsatellite genotypes (hypothesis 1). High levels of gene flow and weak genetic clustering of populations indicate a lack of differentiation, therefore an interaction between climate and local genotype (hypothesis 2) seems unlikely. Our results suggest that C. aquaticum may not have ''tightly'' coevolved with its host Eichhornia spp. (Pontederiaceae) as originally thought, and that instar variation might be due to the effect of local climate on phenotype (hypothesis 3) or possibly a locally adaptive trait.

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Section: Historical Structure and The Influence Of Current Climatic Vsupporting

confidence: 89%

What is responsible for the variance in life history traits of a South American semi‐aquatic grasshopper (Cornops aquaticum)? A test of three possible hypotheses

Brede

Adis

Schneider

2007

Studies on Neotropical Fauna and Environment

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“…This allows females to become considerably larger than males in milder conditions, similarly to what was observed in C. cazurroi and C. yersini . Notably, C. parallelus is one of the few Chorthippus of which the female is unable to change the number of instars during development when exposed to varying heat supplies (Schädler & Witsack, ). This implies that this species may respond less readily to shifting thermal conditions as compared to its congeners, a fact that may constrain its distribution to the mildest niche and impede an upward expansion as species showing a greater flexibility of responses (Hodkinson, ).…”

Section: Discussionmentioning

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

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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.

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“…In contrast, C. parallelus exhibits a very strong positive size cline ratio (i.e., greater variability in male size; Fig. 2b) and is one of the few species in the Chorthippus genus for which females cannot alter the number of instars during development (Schädler and Witsack 1999). This fixed instar number may act to constrain variability in female body size across altitudinal gradients; hence the observations of Laiolo et al (2013).…”

Section: Discussionmentioning

confidence: 99%

A synthesis of major environmental-body size clines of the sexes within arthropod species

2019

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Body size at maturity often varies with environmental conditions, as well as between males and females within a species [termed Sexual Size Dimorphism (SSD)]. Variation in body size clines between the sexes can determine the degree to which SSD varies across environmental gradients. We use a meta-analytic approach to investigate whether major biogeographical and temporal (intra-annually across seasons) body size clines differ systematically between the sexes in arthropods. We consider 329 intra-specific environmental gradients in adult body size across latitude, altitude and with seasonal temperature variation, representing 126 arthropod species from 16 taxonomic orders. On average, we observe greater variability in male than female body size across latitude, consistent with the hypothesis that, over evolutionary time, directional selection has acted more strongly on male than female size. In contrast, neither sex exhibits consistently greater proportional changes in body size than the other sex across altitudinal or seasonal gradients, akin to earlier findings for plastic temperature-size responses measured in the laboratory. Variation in the degree to which body size gradients differ between the sexes cannot be explained by a range of potentially influential factors, including environment type (aquatic vs. terrestrial), voltinism, mean species’ body size, degree of SSD, or gradient direction. Ultimately, if we are to make better sense of the patterns (or lack thereof) in SSD across environmental gradients, we require a more detailed understanding of the underlying selective pressures driving clines in body size. Such understanding will provide a more comprehensive hypothesis-driven approach to explaining biogeographical and temporal variation in SSD. Electronic supplementary material The online version of this article (10.1007/s00442-019-04428-7) contains supplementary material, which is available to authorized users.

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Variation of Postembryonic Development Time and Number of Nymphal Instars on a Small Spatial Scale in Central European Grasshoppers (Caelifera: Acrididae)

Cited by 8 publications

References 0 publications

What is responsible for the variance in life history traits of a South American semi‐aquatic grasshopper (Cornops aquaticum)? A test of three possible hypotheses

What is responsible for the variance in life history traits of a South American semi‐aquatic grasshopper (Cornops aquaticum)? A test of three possible hypotheses

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

A synthesis of major environmental-body size clines of the sexes within arthropod species

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