scholarly journals Body size affects the evolution of hidden colour signals in moths

2017 ◽  
Vol 284 (1861) ◽  
pp. 20171287 ◽  
Author(s):  
Changku Kang ◽  
Reza Zahiri ◽  
Thomas N. Sherratt
Keyword(s):  
Body Size ◽  
Large Prey ◽  
Large Species ◽  
Large Size ◽  
The Family ◽  
General Mathematical Model ◽  
Selection For ◽  
Behavioural Experiments ◽  
Comparative Phylogenetic Analysis ◽  
Colour Signals

Many cryptic prey have also evolved hidden contrasting colour signals which are displayed to would-be predators. Given that these hidden contrasting signals may confer additional survival benefits to the prey by startling/intimidating predators, it is unclear why they have evolved in some species, but not in others. Here, we have conducted a comparative phylogenetic analysis of the evolution of colour traits in the family Erebidae (Lepidoptera), and found that the hidden contrasting colour signals are more likely to be found in larger species. To understand why this relationship occurs, we present a general mathematical model, demonstrating that selection for a secondary defence such as deimatic display will be stronger in large species when (i) the primary defence (crypsis) is likely to fail as its body size increases and/or (ii) the secondary defence is more effective in large prey. To test the model assumptions, we conducted behavioural experiments using a robotic moth which revealed that survivorship advantages were higher against wild birds when the moth has contrasting hindwings and large size. Collectively, our results suggest that the evolutionary association between large size and hidden contrasting signals has been driven by a combination of the need for a back-up defence and its efficacy.

scholarly journals Body size affects the evolution of eyespots in caterpillars

2015 ◽  
Vol 112 (21) ◽  
pp. 6664-6669 ◽  
Author(s):  
Thomas John Hossie ◽  
John Skelhorn ◽  
Jesse W. Breinholt ◽  
Akito Y. Kawahara ◽  
Thomas N. Sherratt
Keyword(s):  
Body Size ◽  
Large Body ◽  
Large Prey ◽  
Laboratory Setting ◽  
Large Body Size ◽  
Small Prey ◽  
Avian Predators ◽  
Predator Attack ◽  
Large Size ◽  
Selection For

Many caterpillars have conspicuous eye-like markings, called eyespots. Despite recent work demonstrating the efficacy of eyespots in deterring predator attack, a fundamental question remains: Given their protective benefits, why have eyespots not evolved in more caterpillars? Using a phylogenetically controlled analysis of hawkmoth caterpillars, we show that eyespots are associated with large body size. This relationship could arise because (i) large prey are innately conspicuous; (ii) large prey are more profitable, and thus face stronger selection to evolve such defenses; and/or (iii) eyespots are more effective on large-bodied prey. To evaluate these hypotheses, we exposed small and large caterpillar models with and without eyespots in a 2 × 2 factorial design to avian predators in the field. Overall, eyespots increased prey mortality, but the effect was particularly marked in small prey, and eyespots decreased mortality of large prey in some microhabitats. We then exposed artificial prey to naïve domestic chicks in a laboratory setting following a 2 × 3 design (small or large size × no, small, or large eyespots). Predators attacked small prey with eyespots more quickly, but were more wary of large caterpillars with large eyespots than those without eyespots or with small eyespots. Taken together, these data suggest that eyespots are effective deterrents only when both prey and eyespots are large, and that innate aversion toward eyespots is conditional. We conclude that the distribution of eyespots in nature likely results from selection against eyespots in small caterpillars and selection for eyespots in large caterpillars (at least in some microhabitats).

scholarly journals Aspects of temperature regulation in mice selected for large and small size

1984 ◽  
Vol 43 (3) ◽  
pp. 299-306 ◽  
Author(s):  
Carol Becker Lynch ◽  
R. C. Roberts
Keyword(s):  
Body Size ◽  
Food Consumption ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Temperature Adaptation ◽  
Behavioural Thermoregulation ◽  
Large Size ◽  
Brown Adipose ◽  
Selection For ◽  
Specific Food

SUMMARYWe measured traits involved in physiological and behavioural thermoregulation in the 6 replicates of a selection experiment for large and small size (6-week weight) in mice, including control lines (18 lines in all). The observed genetic correlations between body size and thermoregulatory traits are consistent with a thermoregulatory advantage of large size, including decreased weight-specific food consumption and increased nest-building, with no change in body temperature. The differences in food consumption were closely paralleled by differences in amount of brown adipose tissue, strongly suggesting that much of the decreased efficiency of the small lines is due to heat production by brown fat. These results are consistent with available observations on natural populations, that selection for temperature adaptation probably has had some influence on body size in this species.

scholarly journals Polychaete Annelid Biomass Size Spectra: The Effects of Hypoxia Stress

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Fangyuan Qu ◽  
Clifton Nunnally ◽  
Gilbert T. Rowe
Keyword(s):  
Body Size ◽  
Continental Shelf ◽  
Large Species ◽  
Size Spectra ◽  
Entire Study ◽  
Hypoxic Conditions ◽  
Wet Weight ◽  
The Mean ◽  
Selection For ◽  
Louisiana Continental Shelf

Quantitative benthic samples were taken during spring and summer at three locations on the Louisiana continental shelf from 2004 to 2012 to assess the influence of hypoxia on the mean sizes (wet weight) of polychaete annelid worms. While the mean body size over the entire study of 64 samples was 3.99 ± 4.66 mg wet weight per individual, the mean ranged from 2.97 ± 2.87 mg during consistently hypoxic conditions (<2 mg/L) to a high of 7.13 ± 7.60 mg (p<0.01) under oxic conditions (>2 mg/L). The variations in size within assemblages were estimated from conventional biomass size spectra (BSS) and normalized biomass size spectra (NBSS) across a broad range of oxygen concentrations. The decline in size was due to the elimination of large species under hypoxic conditions (<2 mg/L), not a reduction in size within species. At “severe” levels of hypoxia (<1 mg/L), the smallest species also declined in abundance, whereas the ubiquitous “medium-sized”Paraprionospio pinnataflourished. These results suggest that there will be enhanced selection for small sizes and species with enlarged branchial palps such as those inP. pinnataif, as predicted, hypoxia becomes more commonplace in time and space worldwide.

Observations on activity, display behavior, coloration and androgen levels in the keeled earless lizard, Holbrookia propinqua

1991 ◽  
Vol 12 (1) ◽  
pp. 57-66 ◽  
Author(s):  
William E. Cooper ◽  
Louis J. Guillette
Keyword(s):  
Body Size ◽  
Small Sample Size ◽  
Small Sample ◽  
Male Body ◽  
Observation Distance ◽  
Large Size ◽  
Color Morphs ◽  
Body Sizes ◽  
Selection For ◽  
The Relationship

AbstractWe observed the distance moved, number of movements, and frequency of displays in ten minute intervals for two male color morphs, coral and yellow, and for brightly colored females, of Holbrookia propinqua. We also measured body sizes and, for males, plasma androgen concentrations. Distance moved, number of movements, and number of social displays were positively correlated in males. Females exhibited similar correlations, but the relationship between distance moved and number of displays was not significant. Males moved more often and greater distances than females. Females performed displays as frequently as did males, perhaps because we selected large, dominant females for observation. Distance moved, number of movements, and number of displays increased with body size in males. That these relationships did not hold in females may indicate a sex difference or reflect the small sample size and body size range of females. Plasma androgen concentrations increased with male body size, suggesting a possible androgenic mechanism of sexual selection for large size. Androgen level did not affect display frequency or distance moved. Distance moved increased with plasma androgen concentration, but when effects of body size were held constant, this relationship vanished. Coral and yellow males did not differ in androgen concentration, size, or in the observed behaviors.

Anacroneuria spp. (Insecta: Plecoptera: Perlidae) as paratenic hosts of Pheromermis sp. (Nematoda: Mermithidae) in Venezuela

Nematology ◽  
2012 ◽  
Vol 14 (2) ◽  
pp. 185-190 ◽  
Author(s):  
Maribet Gamboa ◽  
Maria Mercedes Castillo ◽  
Ricardo Guerrero
Keyword(s):  
Body Size ◽  
Body Regions ◽  
Individual Host ◽  
The Family ◽  
Paratenic Hosts

Nematodes of the family Mermithidae are known as endoparasites of freshwater arthropods. Juveniles of Pheromermis sp. (Mermithidae) were found coiled inside stonefly nymphs collected at seven sites in the Guare and Emilia rivers in northern Venezuela. Prevalence in Anacroneuria blanca was 93.2% () and in A. caraca was 91.5% (). In A. blanca, a higher number of juveniles per individual host was observed than in A. caraca, a fact that is probably related to body size. Although parasites were observed in all body regions, the highest incidence occurred in the legs and thorax. Considering the nematode prevalence and intensity of parasitism, we consider individuals of Anacroneuria spp. to be important hosts of Pheromermis in these rivers.

Prey Body Size and Ranking in Zooarchaeology: Theory, Empirical Evidence, and Applications from the Northern Great Basin

2011 ◽  
Vol 76 (3) ◽  
pp. 403-428 ◽  
Author(s):  
Jack M. Broughton ◽  
Michael D. Cannon ◽  
Frank E. Bayham ◽  
David A. Byers
Keyword(s):  
Body Size ◽  
Great Basin ◽  
Diet Breadth ◽  
Foraging Theory ◽  
Return Rate ◽  
The Body ◽  
Foraging Efficiency ◽  
Large Prey ◽  
Abundance Indices ◽  
Game Hunting

The use of body size as an index of prey rank in zooarchaeology has fostered a widely applied approach to understanding variability in foraging efficiency. This approach has, however, been critiqued—most recently by the suggestion that large prey have high probabilities of failed pursuits. Here, we clarify the logic and history of using body size as a measure of prey rank and summarize empirical data on the body size-return rate relationship. With few exceptions, these data document strong positive relationships between prey size and return rate. We then illustrate, with studies from the Great Basin, the utility of body size-based abundance indices (e.g., the Artiodactyl Index) when used as one component of multidimensional analyses of prehistoric diet breadth. We use foraging theory to derive predictions about Holocene variability in diet breadth and test those predictions using the Artiodactyl Index and over a dozen other archaeological indices. The results indicate close fits between the predictions and the data and thus support the use of body size-based abundance indices as measures of foraging efficiency. These conclusions have implications for reconstructions of Holocene trends in large game hunting in western North America and for zooarchaeological applications of foraging theory in general.

scholarly journals Atmospheric Hypoxia Limits Selection for Large Body Size in Insects

PLoS ONE ◽  
2009 ◽  
Vol 4 (1) ◽  
pp. e3876 ◽  
Author(s):  
C. Jaco Klok ◽  
Jon F. Harrison
Keyword(s):  
Body Size ◽  
Large Body ◽  
Large Body Size ◽  
Selection For

scholarly journals Continued artificial selection for running endurance in rats is associated with improved lung function

2009 ◽  
Vol 106 (6) ◽  
pp. 1810-1818 ◽  
Author(s):  
Scott D. Kirkton ◽  
Richard A. Howlett ◽  
Norberto C. Gonzalez ◽  
Patrick G. Giuliano ◽  
Steven L. Britton ◽  
...  
Keyword(s):  
Body Size ◽  
Lung Volume ◽  
Maximal Oxygen Consumption ◽  
Endurance Capacity ◽  
Endurance Running ◽  
Body Frame ◽  
Cardiopulmonary Function ◽  
Muscle Adaptations ◽  
Selection For ◽  
Seven Generations

Previous studies found that selection for endurance running in untrained rats produced distinct high (HCR) and low (LCR) capacity runners. Furthermore, despite weighing 14% less, 7th generation HCR rats achieved the same absolute maximal oxygen consumption (V̇o2max) as LCR due to muscle adaptations that improved oxygen extraction and use. However, there were no differences in cardiopulmonary function after seven generations of selection. If selection for increased endurance capacity continued, we hypothesized that due to the serial nature of oxygen delivery enhanced cardiopulmonary function would be required. In the present study, generation 15 rats selected for high and low endurance running capacity showed differences in pulmonary function. HCR, now 25% lighter than LCR, reached a 12% higher absolute V̇o2max than LCR, P < 0.05 (49% higher V̇o2max/kg). Despite the 25% difference in body size, both lung volume (at 20 cmH2O airway pressure) and exercise diffusing capacity were similar in HCR and LCR. Lung volume of LCR lay on published mammalian allometrical relationships while that of HCR lay above that line. Alveolar ventilation at V̇o2max was 30% higher, P < 0.05 (78% higher, per kg), arterial Pco2 was 4.5 mmHg (17%) lower, P < 0.05, while total pulmonary vascular resistance was (insignificantly) 5% lower (30% lower, per kg) in HCR. The smaller mass of HCR animals was due mostly to a smaller body frame rather than to a lower fat mass. These findings show that by generation 15, lung size in smaller HCR rats is not reduced in concert with their smaller body size, but has remained similar to that of LCR, supporting the hypothesis that continued selection for increased endurance capacity requires relatively larger lungs, supporting greater ventilation, gas exchange, and pulmonary vascular conductance.

Three new species of oribatid mites of the family Galumnidae (Acari, Oribatida) from South Africa

Zootaxa ◽  
2021 ◽  
Vol 4920 (1) ◽  
pp. 91-100
Author(s):  
SERGEY G. ERMILOV ◽  
ELIZABETH A. HUGO-COETZEE ◽  
ALEXANDER A. KHAUSTOV
Keyword(s):  
South Africa ◽  
New Species ◽  
Body Size ◽  
Oribatid Mites ◽  
Eastern Cape Province ◽  
Eastern Cape ◽  
The Family ◽  
Three New Species ◽  
Porose Area ◽  
Median Pore

Three new species of oribatid mites of the family Galumnidae are described from soil and coniferous litter of Hogsback State Forest, Eastern Cape Province, South Africa. Pilogalumna hogsbackensis sp. nov. differs from Pilogalumna tenuiclava and P. ornatula by the presence of elongate oval postanal porose area and narrowly unilaterally dilated bothridial head. Pergalumna amatholensis sp. nov. differs from Pergalumna distincta by the presence of smaller body size, rounded rostrum, unilaterally dilated bothridial head, one pair of notogastral porose areas Aa, and the localization of opisthonotal gland opening and lyrifissure im. Stictozetes ihaguensis sp. nov. differs from all species of the genus by presence of bothridial seta with narrowly dilated head and median pore in both genders. An identification key to known species of Stictozetes is presented. 

Three Approaches for Managing Stiffness in Origami-Inspired Mechanisms

2018 ◽  
Author(s):  
Alden Yellowhorse ◽  
Larry L. Howell
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Engineering Applications ◽  
Element Analysis ◽  
Advantages And Disadvantages ◽  
Large Size ◽  
Selection For

Ensuring that deployable mechanisms are sufficiently rigid is a major challenge due to their large size relative to their mass. This paper examines three basic types of stiffener that can be applied to light, origami-inspired structures to manage their stiffness. These stiffeners are modeled analytically to enable prediction and optimization of their behavior. The results obtained from this analysis are compared to results from a finite-element analysis and experimental data. After verifying these models, the advantages and disadvantages of each stiffener type are considered. This comparison will facilitate stiffener selection for future engineering applications.

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