Larval habitats impose trait-dependent limits on the direction and rate of adult evolution in dragonflies

2021 ◽  
Vol 17 (5) ◽  
pp. 20210023
Author(s):  
Michael P. Moore
Keyword(s):  
Natural Selection ◽  
Comparative Study ◽  
Adult Stage ◽  
Larval Habitat ◽  
Adult Size ◽  
Larval Habitats ◽  
Size Evolution ◽  
Fitness Benefits ◽  
Context Dependent ◽  
Ornament Evolution

Natural selection on juveniles is often invoked as a constraint on adult evolution, but it remains unclear when such restrictions will have their greatest impact. Selection on juveniles could, for example, mainly limit the evolution of adult traits that mostly develop prior to maturity. Alternatively, selection on juveniles might primarily constrain the evolution of adult traits that experience weak or context-dependent selection in the adult stage. Using a comparative study of dragonflies, I tested these hypotheses by examining how a species’ larval habitat was related to the evolution of two adult traits that differ in development and exposure to selection: adult size and male ornamentation. Whereas adult size is fixed at metamorphosis and experiences consistent positive selection in the adult stage, ornaments develop throughout adulthood and provide context-dependent fitness benefits. My results show that species that develop in less stable larval habitats have smaller adult sizes and slower rates of adult size evolution. However, these risky larval habitats do not limit ornament expression or rates of ornament evolution. Selection on juveniles may therefore primarily affect the evolution of adult traits that mostly develop prior to maturity.

scholarly journals Predicting distribution of malaria vector larval habitats in Ethiopia by integrating distributed hydrologic modeling with remotely sensed data

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ai-Ling Jiang ◽  
Ming-Chieh Lee ◽  
Guofa Zhou ◽  
Daibin Zhong ◽  
Dawit Hawaria ◽  
...  
Keyword(s):  
Malaria Vector ◽  
Malaria Control ◽  
Remotely Sensed ◽  
Larval Habitat ◽  
Validation Dataset ◽  
Significant Shift ◽  
Remotely Sensed Data ◽  
Larval Habitats ◽  
Common Land Model ◽  
The Impact

AbstractLarval source management has gained renewed interest as a malaria control strategy in Africa but the widespread and transient nature of larval breeding sites poses a challenge to its implementation. To address this problem, we propose combining an integrated high resolution (50 m) distributed hydrological model and remotely sensed data to simulate potential malaria vector aquatic habitats. The novelty of our approach lies in its consideration of irrigation practices and its ability to resolve complex ponding processes that contribute to potential larval habitats. The simulation was performed for the year of 2018 using ParFlow-Common Land Model (CLM) in a sugarcane plantation in the Oromia region, Ethiopia to examine the effects of rainfall and irrigation. The model was calibrated using field observations of larval habitats to successfully predict ponding at all surveyed locations from the validation dataset. Results show that without irrigation, at least half of the area inside the farms had a 40% probability of potential larval habitat occurrence. With irrigation, the probability increased to 56%. Irrigation dampened the seasonality of the potential larval habitats such that the peak larval habitat occurrence window during the rainy season was extended into the dry season. Furthermore, the stability of the habitats was prolonged, with a significant shift from semi-permanent to permanent habitats. Our study provides a hydrological perspective on the impact of environmental modification on malaria vector ecology, which can potentially inform malaria control strategies through better water management.

scholarly journals Sugarcane stems as larval habitat for the stable fly (Stomoxys calcitrans) in sugarcane plantations

2013 ◽  
Vol 33 (6) ◽  
pp. 741-744 ◽  
Author(s):  
Paulo H.D. Cançado ◽  
Taciany Ferreira ◽  
Eliane M. Piranda ◽  
Cleber O. Soares
Keyword(s):  
Primary Source ◽  
Weather Conditions ◽  
Larval Habitat ◽  
Stomoxys Calcitrans ◽  
Stable Fly ◽  
Mato Grosso ◽  
Larval Habitats ◽  
Control Programs ◽  
Bad Weather ◽  
Mato Grosso Do Sul

Outbreaks of stable fly, Stomoxys calcitrans, cause losses for livestock producers located near sugarcane mills in Brazil, especially in southern Mato Grosso do Sul. The sugarcane mills are often pointed by local farmers as the primary source of these outbreaks; some mills also joined the farmers in combating the flies. Brazilian beef cattle production has great economic importance in similar level to bio-fuel production as ethanol. In this context, the wide-ranging knowledge on the biology and ecology of the stable fly, including larval habitats and their reproduction sites is extremely important for further development of control programs. This paper aims to report the occurrence and development of S. calcitrans larvae inside sugarcane stems in three municipalities of Mato Grosso do Sul. The sugarcane stems give protection against bad weather conditions and insecticide application. In this way, for sustainable sugarcane growth specific research concerning this situation should be conducted.

Effects of initial (larval) size and host body temperature on growth in trematodes

2003 ◽  
Vol 81 (4) ◽  
pp. 574-581 ◽  
Author(s):  
Robert Poulin ◽  
A David M. Latham
Keyword(s):  
Body Size ◽  
Body Temperature ◽  
Adult Stage ◽  
Species Variation ◽  
Adult Size ◽  
Model Group ◽  
Larval Size ◽  
Relative Growth ◽  
Host Body ◽  
Adult Body

For ectotherms, temperature is an important correlate of variation in body size within species. Variation in body size among related species could also be attributable in part to temperature if the different species grow under different thermal regimes. The roles of both initial (larval) size and host body temperature on final (adult) size of parasitic trematodes were investigated in a comparative analysis. Trematodes are a good model group for such a study, with almost half of known species growing at high and constant temperatures in endothermic vertebrates and the rest at lower and fluctuating temperatures in ectothermic vertebrates. The relative growth of trematodes, i.e., their growth relative to the size of their larvae, varied greatly among species. Increases in body size from the cercarial larval stage to the adult stage averaged almost 40-fold (maximum 1300-fold), whereas increases in size from the metacercarial stage to the adult stage averaged 6-fold (maximum 110-fold). There were no differences between trematodes in ectothermic hosts and trematodes in endothermic hosts with respect to these measures of relative growth, however, which suggests that host type and the thermal regime provided by the host have no effect on the growth of trematodes from larval to adult stages. In contrast, the final (adult) body size of trematodes appears to be determined to some extent by their initial (larval) size, independently of the type of host in which they developed.

scholarly journals Bigger is not always better: when brains get smaller

2005 ◽  
Vol 1 (3) ◽  
pp. 283-286 ◽  
Author(s):  
Kamran Safi ◽  
Marc A Seid ◽  
Dina K.N Dechmann
Keyword(s):  
Natural Selection ◽  
Brain Size ◽  
Ancestral State ◽  
Size Evolution ◽  
Bidirectional Selection

Many studies assume that an increase in brain size is beneficial. However, the costs of producing and maintaining a brain are high, and we argue that brain size should be secondarily reduced by natural selection whenever the costs outweigh the benefits. Our results confirm this by showing that brain size is subject to bidirectional selection. Relative to the ancestral state, brain size in bats has been reduced in fast flyers, while it has increased in manoeuvrable flyers adapted to flight in complex habitats. This study emphasizes that brain reduction and enlargement are equally important, and they should both be considered when investigating brain size evolution.

scholarly journals Natural selection and context-dependent values

1997 ◽  
Vol 264 (1387) ◽  
pp. 1539-1541 ◽  
Author(s):  
Alasdair I. Houston
Keyword(s):  
Natural Selection ◽  
Context Dependent

Species composition and abundance of mosquito larvae in relation with their habitat characteristics in Mazandaran Province, northern Iran

2017 ◽  
Vol 107 (5) ◽  
pp. 598-610 ◽  
Author(s):  
S.H. Nikookar ◽  
M. Fazeli-Dinan ◽  
S. Azari-Hamidian ◽  
S.N. Mousavinasab ◽  
M. Arabi ◽  
...  
Keyword(s):  
Environmental Variables ◽  
Larval Density ◽  
Larval Habitat ◽  
Habitat Characteristics ◽  
Mosquito Larvae ◽  
Mazandaran Province ◽  
Natural Habitats ◽  
Northern Iran ◽  
Monthly Basis ◽  
Larval Habitats

AbstractMosquitoes transmit a variety of diseases to humans. Their abundance and distribution are related to the characteristics of larval habitats. Mosquito larvae were collected from 120 natural and artificial habitats in 30 villages of 16 counties using standard 350 ml dippers and pipette, on a monthly basis from May–December 2014 in Mazandaran Province, northern Iran. Larval habitat characteristics were recorded separately, based on the conditions of the habitats (permanent or temporary, stagnant or running), type of habitats (natural or artificial), vegetation, exposure to sun, type of bed, water condition (clear or turbid), expanse (m), depth (cm, m) and temperature (°C) of habitats. The relationship between larval density and environmental variables was assessed by Chi-square tests. Totally, 19,840 larvae from three genera and 16 species were collected and identified.Anopheles maculipennis s.l.andCulex pipienswere the dominant species and collected with the highest density in plain areas. The highest number of larvae were collected from natural habitats (60.34%), including; river edge, marsh, pit and wetlands; with temporary and stagnant water, expanse of 0–5 m, depth of 1–25 cm, without plant, shadow-sun, muddy floor, turbid water, temperature 20–25°C and in sunny conditions. River edge and rice fields forAn. maculipennis s.land, wetlands and discarded tires forCx. pipienswere the main larval habitats in the province. Statistical analysis revealed significant relation between occurrence ofAn. maculipennis s.l., Cx. pipiens, Culex torrentium, Culex mimeticusandCs. annulatawith each of the environmental variables (P< 0.001). These findings are essential in expanding our knowledge of the vectors ecology specially the type of habitat preference and will be beneficial in larval control programs.

The Differentiation of Coenurus species by Hook Measurements

1941 ◽  
Vol 19 (3-4) ◽  
pp. 75-84 ◽  
Author(s):  
P. A. Clapham ◽  
B. G. Peters
Keyword(s):  
Standard Deviation ◽  
Adult Stage ◽  
Adult Size ◽  
Limited Data ◽  
Single Cyst ◽  
Mean Dimension ◽  
The Mean

Hook dimensions of Multiceps glomeratus show that the hooks are capable of reaching full adult size in the coenurus stage.The available material showed that M. serialis hooks were slightly larger than those of M. glomeratus in the adult stage; in the coenurus stage the differences were not significant.Statistically, the dimensions measuring the length of the blade of the hook are the most satisfactory.There are significantly large variances in most cystic hook dimensions from one cyst to another, and from one scolex to another within a single cyst, but not from one group of scolices to another. It follows that in biometric work it is important to sample several scolices from each cyst, and several cysts of any one species, but that groups can be disregarded.The variability of most hook measurements is in the region of 5%; i.e. the standard deviation is about 5% of the mean dimension.The danger of extensive generalisation from limited data should be guarded against. Thus, while the species variance was significantly larger than the cyst variance in the case of adult hooks in the material available, it is quite possible that this would no longer have been the case if material from other sources had been available.

scholarly journals Bioecology of Dominant Malaria Vector, Anopheles superpictus s.l. Grassi (Diptera: Culicidae) In Iran

2018 ◽  
Author(s):  
Hassan Vatandoost ◽  
Ahmad Ali Hanafi-Bojd ◽  
Ahmad Raeisi ◽  
Mohammad Reza Abai ◽  
Fatemeh Nikpour
Keyword(s):  
Public Health ◽  
Public Health Problem ◽  
Larval Habitat ◽  
Malaria Vectors ◽  
Related Factors ◽  
Larval Habitats ◽  
Sustainability Index ◽  
Adult Females ◽  
Flight Range ◽  
Vector Borne

Background: Malaria continues to be a main vector-borne public health problem in Iran. The endemic foci of the dis­ease are mainly located in south-eastern part of the country. Iran is now launching the elimination of malaria. Studies on the bioecology and susceptibility of malaria vectors to insecticide are essential in this phase. Methods: The literature on bio-ecology of Anopheles superpictus s.l. Grassi was reviewed in Iran in more than half a century. Different aspects including, distribution, key identification, larval habitats, flight range, seasonal activities, irritability/susceptibility to insecticides, and anthropophilicity index were identified. Results: The adult females of An. superpictus s.l. were susceptible to all WHO-recommended imagicides except DDT. Distribution, morphology, sibling species, larval habitat, flight range, Irritability tests, sustainability index, blood feed­ing preference and related factors were discussed in details Conclusion: Results of the evaluating will help for decision making of authorities for vector control.

scholarly journals A comparative test of the gamete dynamics theory for the evolution of anisogamy in Bryopsidales green algae

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Tatsuya Togashi ◽  
Yusuke Horinouchi ◽  
Geoff A. Parker
Keyword(s):  
Life Cycle ◽  
Green Algae ◽  
Adult Stage ◽  
Male Gamete ◽  
Comparative Test ◽  
Disruptive Selection ◽  
Adult Size ◽  
Male Gametes ◽  
Selection For ◽  
Gamete Size

Gamete dynamics theory proposes that anisogamy arises by disruptive selection for gamete numbers versus gamete size and predicts that female/male gamete size (anisogamy ratio) increases with adult size and complexity. Evidence has been that in volvocine green algae, the anisogamy ratio correlates positively with haploid colony size. However, green algae show notable exceptions. We focus on Bryopsidales green algae. While some taxa have a diplontic life cycle in which a diploid adult (=fully grown) stage arises directly from the zygote, many taxa have a haplodiplontic life cycle in which haploid adults develop indirectly: the zygote first develops into a diploid adult (sporophyte) which later undergoes meiosis and releases zoospores, each growing into a haploid adult gametophyte. Our comparative analyses suggest that, as theory predicts: (i) male gametes are minimized, (ii) female gamete sizes vary, probably optimized by number versus survival as zygotes, and (iii) the anisogamy ratio correlates positively with diploid (but not haploid) stage complexity. However, there was no correlation between the anisogamy ratio and diploid adult stage size. Increased environmental severity (water depth) appears to drive increased diploid adult stage complexity and anisogamy ratio: gamete dynamics theory correctly predicts that anisogamy evolves with the (diploid) stage directly provisioned by the zygote.

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