scholarly journals Sensory Organ Investment Varies with Body Size and Sex in the Butterfly Pieris napi

Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1064
Author(s):  
Zahra Moradinour ◽  
Christer Wiklund ◽  
Vun Wen Jie ◽  
Carlos E. Restrepo ◽  
Karl Gotthard ◽  
...  

In solitary insect pollinators such as butterflies, sensory systems must be adapted for multiple tasks, including nectar foraging, mate-finding, and locating host-plants. As a result, the energetic investments between sensory organs can vary at the intraspecific level and even among sexes. To date, little is known about how these investments are distributed between sensory systems and how it varies among individuals of different sex. We performed a comprehensive allometric study on males and females of the butterfly Pieris napi where we measured the sizes and other parameters of sensory traits including eyes, antennae, proboscis, and wings. Our findings show that among all the sensory traits measured, only antenna and wing size have an allometric relationship with body size and that the energetic investment in different sensory systems varies between males and females. Moreover, males had absolutely larger antennae and eyes, indicating that they invest more energy in these organs than females of the same body size. Overall, the findings of this study reveal that the size of sensory traits in P. napi are not necessarily related to body size and raises questions about other factors that drive sensory trait investment in this species and in other insect pollinators in general.

Insects ◽  
2018 ◽  
Vol 9 (3) ◽  
pp. 108 ◽  
Author(s):  
Kaan Kerman ◽  
Angela Roggero ◽  
Antonio Rolando ◽  
Claudia Palestrini

Male horn dimorphism is a rather common phenomenon in dung beetles, where some adult individuals have well-developed head horns (i.e., major males), while others exhibit diminished horn length (i.e., minor males). We focused on horn dimorphism and associated head and pronotum shape variations in Copris lunaris. We examined the allometric relationship between horn length (i.e., cephalic and pronotal horns) and maximum pronotum width (as index of body size) by fitting linear and sigmoidal models for both sexes. We then asked whether head and pronotum shape variations, quantified using the geometric morphometric approach, contributed to this allometric pattern. We found that female cephalic and pronotal horn growth showed a typical isometric scaling with body size. Horn length in males, however, exhibited sigmoidal allometry, where a certain threshold in body size separated males into two distinct morphs as majors and minors. Interestingly, we highlighted the same allometric patterns (i.e., isometric vs. sigmoidal models) by scaling horn lengths with pronotum shape, making evident that male horn dimorphism is not only a matter of body size. Furthermore, the analysis of shape showed that the three morphs had similar heads, but different pronota, major males showing a more expanded, rounded pronotum than minor males and females. These morphological differences in C. lunaris can ultimately have important functional consequences in the ecology of this species, which should be explored in future work.


2015 ◽  
Vol 90 (2) ◽  
pp. 186-198 ◽  
Author(s):  
S.V. Malysheva

AbstractOzolaimus linstowin. sp. is described from the large intestine ofIguana iguanaLinnaeus, 1758 from Mexico. The present species can be easily distinguished fromO. megatyphlonandO. cirratusby the presence of a long and slender pharynx not divided into sections, more similar to the remaining two species,O. monhysteraandO. ctenosauri. Ozolaimus linstowin. sp. can be differentiated fromO. monhysteraby the shorter spicule length and smaller body size of both males and females. Males ofO. linstowin. sp. are morphologically close to those ofO. ctenosauri, but females possess a markedly smaller body size and differ in the organization of the oral cuticular armature. Adult males ofO. linstowin. sp. bear some characteristic features of the J3 juvenile morphology in terms of the cuticular organization of the oral and buccal capsule. Phylogenetic analysis ofO.linstowin. sp. using partial small subunit (SSU) and D2–D3 large subunit (LSU) rDNA shows relationships with several Oxyuridae genera.


1966 ◽  
Vol 98 (6) ◽  
pp. 639-644 ◽  
Author(s):  
B. C. Smith

AbstractThe weight and size of coccinellid adults varied with species, sex, and feeding. Intraspecies variation in weight was generally similar in the eight species studied. Females were more variable than males in body size. Females of some species were heavier and larger than males, and species can be classified on a basis of difference in the weight and size of the sexes.An increase in the food supply after a period of food scarcity affected the sex ratio, as the minimum food requirement of females was greater than males. Females increased in weight more rapidly than males after feeding. The availability of food in the field affected the weight and size of some species. Adult water content was influenced by feeding but not by sex or the quantity of food given to the larva.Males were more abundant in species with small sexual differences in weight and size. The degree of difference in weight and size between males and females may be used as a criterion to select species that are best adapted to survive when food is scarce.


2019 ◽  
Vol 97 (3) ◽  
pp. 220-224 ◽  
Author(s):  
H.V. Watkins ◽  
G. Blouin-Demers

Determining the factors that influence parasite load is a fundamental goal of parasitology. Body size often influences parasite load in reptiles, but it is unclear whether higher levels of parasitism are a result of greater surface area of individuals (a function of size) or of longer periods of exposure to parasites (a function of age). Using skeletochronology in a wild population of Clark’s Spiny Lizards (Sceloporus clarkii Baird and Girard, 1852), we tested the hypotheses that (i) larger individuals have higher parasite loads due to increased surface area available for colonization by parasites and their vectors and that (ii) older individuals have higher parasite loads because they have had longer exposure to parasites and their vectors. Males harboured more ectoparasites than females. Males and females differed in how body size influenced chigger (Acari: Trombiculidae) load; larger males harboured more chiggers than smaller males, but this was not the case in females. Age did not affect ectoparasite load in either sex. These results emphasize the importance of disentangling the effects of size and age in models of parasitism to gain a clearer understanding of intraspecific variation in parasite load.


2018 ◽  
Vol 41 ◽  
pp. 13-18
Author(s):  
Olav Hogstad ◽  
Tore Slagsvold

The Willow Tit Poecile montanus is highly sedentary and breeding pairs remain in their exclusive areas throughout the year. During the winter, these areas are defended by small, non-kin flocks, formed as the roaming yearlings become sedentary and join adults during late summer and autumn. Once established, stable social hierarchies are maintained in these flocks during the winter. The winter flocks consist normally of the socially dominant adult mated pair and two mated juvenile pairs, one higher-ranked and one lower-ranked. Individually colour-ringed juvenile Willow Tits were followed over years in subalpine forest in Norway from ringing in the autumn till they disappeared. None of the lower ranked birds survived their first winter, whereas only 4 of 71 higher-ranked juvenile pairs disappeared during this time. Half of the 71 pairs survived their first winter, about 25 % survived two winters, 8.5% survived three winters, and 5.6% survived four winters. Survival was similar for males and females. Alpha pairs remained mated and defended their common territory across years. Maximum age as revealed by ringing showed one female became six years old and two males ringed as adults were at least nine years old when last observed. The main factor associated with survival was early flock establishment that led to a high rank position among the juvenile flock members. Body size seemed insignificant. Birds that survived their first winter either succeeded to establish as territory owners or they were forced into the role as floaters and probably perished.


Author(s):  
P. M. Parés- Casanova ◽  
A. Kabir

Sexual dimorphism, defined as phenotypic differences between males and females, is a common phenomenon in animals. In this line, Rensch’s rule states that sexual size dimorphism increases with increasing body size when the male is the larger sex and decreases with increasing average body size when the female is the larger sex. Domesticated animals offer excellent opportunities for testing predictions of functional explanations of Rensch’s theory. Pigeon breeds encounters many different functional purposes and selective constraints, which could influence strongly their morphology. The aim of this paper is to examine, for first time, Rensch’s rule among domestic pigeons. It was compiled a database of 12 quantitative traits (body weight, body height, beak thickness, beak length, neck length, neck thickness, wing length, rump width, tail length, tarsus length, tarsus thickness and middle toe length) for males and females of 11 different domestic pigeon breeds: Bangladesh Indigenous, Racing Homer, Turkish Tumbler, Indian Lotan, Kokah, Mookee, Indian Fantail, Bokhara Trumpeter, Bombai, Lahore and Hungarian Giant House; Rock Pigeon (Columba livia) was also considered as wild relative for comparative purposes. Comparative results between males and females showed that only body weight, wing length and neck thickness were consistent with Rensch’s rule. The rest of trait did not present correlations. Among domestic pigeons, there can appear different expressions of dimorphism according to each trait, so it must be considered that Rensch’s rule vary when considering other traits than body weight.


1962 ◽  
Vol 3 (2) ◽  
pp. 169-180 ◽  
Author(s):  
Forbes W. Robertson

1. Mass selection for both high- and low-ratio of wing to thorax length has been carried out on a population of Drosophila melanogaster. The response to selection was immediate and sustained. When the experiment was stopped after ten generations, the wing area in the two selected lines differed by about 30%. The heritability estimate worked out at 0·56 ± 0·08.2. Thorax length remained comparatively unchanged during selection nor was there any change in wing shape. There was some evidence of assymetry of response since there was a relatively greater change in favour of smaller rather than larger size.3. The tibia length of all pairs of legs showed correlated changes so that the lines with larger or smaller wing sizes had also larger and smaller legs.4. The normal allometric relation between wing and thorax length, associated with variation in body-size, apparently also changed, so that for a given change in thorax length there was a greater or smaller proportional change in wing size in the high- or low-ratio lines.5. The changes in relative wing size are due to changes in cell number.6. It is suggested that the genetic changes due to selection act in the early pupal period when the imaginal discs are undergoing differentiation and proliferation to form imaginal hypoderm and appendages.7. Tests of genetic behaviour failed to show any departure from additivity in crosses which involved the unselected population and the high-ratio line. But highly significant departures existed in the cross to the low-ratio line. Relatively smaller wing size behaves as largely recessive. Stability of the normal wing/thorax ratio involves dominance and probably also epistasis. The genetic properties of the relative size of the appendage are apparently similar to those which characterize body-size as a whole.8. It is suggested that selection provides a valuable tool for studying the constancy or lability of the growth patterns which determine morphology.


2001 ◽  
Vol 13 (4) ◽  
pp. 392-401 ◽  
Author(s):  
Hans U. Wessel ◽  
Janette F. Strasburger ◽  
Brett M. Mitchell

We have developed normal standards for the Bruce exercise (EX) protocol since a review of 875 studies in patients with congenital or acquired heart disease showed that only 5.1% achieved the predicted 50th percentile for EX time of the standards reported by Cumming, Everatt, and Hastman (Am. J Cardiol 41:69, 1978). Our data are based on 160 males and 103 females, age 4–18 years who met the following criteria: trivial or no heart disease, maximal effort, maximal EX heart rate (HR) > 180 beats/min, and normal resting and EX ECG without arrhythmia. The ECG was monitored continuously and HR computed from the ECG and the end of each minute of EX. Comparison with the predicted data of Cumming et al. for each age group by stage showed essentially identical submaximal EX heart rates but slightly lower maximal HR (–2%), which averaged 197 beats per minute in males and females. EX times were on average 15% lower than the predicted 50th percentile for most age groups in males and females. We developed regression equations, which predict exercise time from age and body size or age, body size and 2nd stage exercise heart rate. They better reflect the capabilities of untrained, asymptomatic children and adolescents seen in our laboratory in the 1990s than the Canadian data of 1978.


2022 ◽  
pp. 27-33
Author(s):  
Tong Lei Yu

Rensch’s rule describes sexual size dimorphism (SSD) that decreases with increasing body size when females are larger than males and SSD that increases when males are larger than females. The plateau brown frog Rana kukunoris, a species endemic to the eastern Tibetan Plateau, exhibits female-biased size dimorphism. Using data on body size from 26 populations and age from 21 populations, we demonstrated that SSD did not increase with increasing mean female snout-vent length (SVL) when controlling for sex-specific age structure, failing to support the Rensch’s rule. Thus, we suggest that fecundity selection (favouring large female size) balances out sexual selection (favouring large male size), which results in a similar divergence between males and females body size. In addition, sex-specific age differences explained most of the variation of SSD across populations.


The Auk ◽  
1987 ◽  
Vol 104 (4) ◽  
pp. 640-646 ◽  
Author(s):  
Ray T. Alisauskas

Abstract I studied morphometric variation in 13 linear measurements from 228 American Coots (Fulica americana) collected in southern Manitoba. Univariate and multivariate techniques revealed differences in size and shape among adult coots that were 1, 2, and =2 yr old. In addition to the obvious differences in size between males and females, the morphometry of older birds differed from that of younger birds in two ways. First, older coots were of larger body size than younger coots of the same sex. Second, older coots had proportionately larger feet and claws relative to the size of their tarsi, and proportionately wider bills and heads relative to other head measurements, than did younger birds. Multivariate dispersion matrices within age/sex cohorts were less variable for older coots. In an analysis of 1-yr-old males, breeders did not differ from nonbreeders in overall body size, but breeders had relatively longer claws and wings than nonbreeders. Age-related differences in morphology may have relevance to the social structure of nesting coots, which involves highly aggressive territorial behavior. Part of the age-related variation in nesting phenology that has been documented elsewhere for coots may be a consequence of covariation in body size and shape.


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