Responses of adult mosquitoes of two sibling species, Anopheles arabiensis and A. gambiae s.s. (Diptera: Culicidae), to high temperatures

2004 ◽  
Vol 94 (5) ◽  
pp. 441-448 ◽  
Author(s):  
M.J. Kirby ◽  
S.W. Lindsay
Keyword(s):  
High Temperatures ◽  
Sibling Species ◽  
Anopheles Arabiensis ◽  
Temporal Distribution ◽  
Sensu Stricto ◽  
Spatial And Temporal Distribution ◽  
Activation Temperature ◽  
Behavioural Avoidance ◽  
Relative Ability ◽  
Increasing Temperature

AbstractIt is well known that amongst the sibling species of the Anopheles gambiae complex, A. arabiensis Patton predominates over A. gambiae sensu stricto Giles in hotter, drier parts of Africa. Here it was investigated whether A. arabiensis is better adapted to higher temperatures than A. gambiae s.s. at the microclimatic level. Bioassays were used to assess behavioural avoidance activity of adult mosquitoes in the presence of increasing temperature. Female mosquitoes were introduced into a holding tube from which they could escape into a cage through a one-way funnel. From a starting temperature of 28°C they were exposed to a 2°C rise in temperature every 30 min until all mosquitoes had escaped or been knocked down. As temperature increased, A. arabiensis left the holding tube at higher temperatures than A. gambiae s.s. (A. arabiensis mean activation temperature = 35.7°C, 95% CIs = 35.4–36.1°C; A. gambiae s.s. = 33.0°C, 32.5–33.5°C). To determine the relative ability of both species to survive at extremely high temperatures, batches of insects were exposed to 40°C for different periods. It took considerably longer to kill 50% of A. arabiensis at 40°C than it did A. gambiae s.s. (112 min vs. 67 min). These data show that adult A. arabiensis are better adapted to hotter conditions than A. gambiae s.s., a characteristic that is reflected in their spatial and temporal distribution in Africa.

Constraints on the Formation of Granite-Related Indium Deposits

2019 ◽  
Vol 114 (5) ◽  
pp. 993-1003 ◽  
Author(s):  
Austin M. Gion ◽  
Philip M. Piccoli ◽  
Philip A. Candela
Keyword(s):  
Hydrothermal System ◽  
Temporal Distribution ◽  
Magnesium Content ◽  
Sensu Stricto ◽  
Spatial And Temporal Distribution ◽  
Magmatic System ◽  
Ore Formation ◽  
Volatile Phase ◽  
Exploration Vectors ◽  
Modern Technologies

Abstract The use of indium in modern technologies has grown in recent decades, creating a growth in indium demand; thus, there is a need to constrain the spatial and temporal distribution of indium-bearing, granite-related deposits. Toward this end, a conceptual model and exploration vectors for the formation of granite-related indium deposits have been developed. The magmatic-hydrothermal system is modeled by consideration of crystal-melt and vapor-melt equilibria. The model calculates the efficiency of removal of indium from a melt into a volatile phase, which may serve as a component of an ore-forming fluid. The results of the model suggest that as the proportion of ferromagnesian minerals increases in the associated granites, the probability of indium ore formation decreases. Further, for a given modal proportion of ferromagnesian minerals, as the modal proportion of amphibole increases, the probability of indium ore formation decreases. Lastly, for a given modal proportion of biotite, as the magnesium content of the biotite increases (as would result from increasing oxidation of the magmatic system), the probability of indium ore formation decreases. Granites with the highest probability of being associated with indium ore formation will typically be part of A- or S-type igneous systems and will likely be highly fractionated (e.g., A-type topaz granites). I-type granites will generally have a lower potential of being associated with indium-bearing deposits. However, some I-type granites may be associated with indium-bearing deposits if the deposits contain granites (sensu stricto) or other related rocks (e.g., alaskites) that lack amphibole or other ferromagnesian phases.

scholarly journals Laboratory and microcosm experiments reveal contrasted adaptive responses to ammonia and water mineralisation in aquatic stages of the sibling species Anopheles gambiae (sensu stricto) and Anopheles coluzzii

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Nwamaka Oluchukwu Akpodiete ◽  
Frédéric Tripet
Keyword(s):  
West Africa ◽  
Anopheles Gambiae ◽  
Emerging Adults ◽  
Sibling Species ◽  
Adult Emergence ◽  
Ecological Speciation ◽  
Sensu Stricto ◽  
Rice Fields ◽  
Anopheles Coluzzii ◽  
Phenotypic Quality

Abstract Background The sibling species of the malaria mosquito, Anopheles gambiae (sensu stricto) and Anopheles coluzzii co-exist in many parts of West Africa and are thought to have recently diverged through a process of ecological speciation with gene flow. Divergent larval ecological adaptations, resulting in Genotype-by-Environment (G × E) interactions, have been proposed as important drivers of speciation in these species. In West Africa, An. coluzzii tends to be associated with permanent man-made larval habitats such as irrigated rice fields, which are typically more eutrophic and mineral and ammonia-rich than the temporary rain pools exploited by An. gambiae (s.s.) Methods To highlight G × E interactions at the larval stage and their possible role in ecological speciation of these species, we first investigated the effect of exposure to ammonium hydroxide and water mineralisation on larval developmental success. Mosquito larvae were exposed to two water sources and increasing ammonia concentrations in small containers until adult emergence. In a second experiment, larval developmental success was compared across two contrasted microcosms to highlight G × E interactions under conditions such as those found in the natural environment. Results The first experiment revealed significant G × E interactions in developmental success and phenotypic quality for both species in response to increasing ammonia concentrations and water mineralisation. The An. coluzzii strain outperformed the An. gambiae (s.s.) strain under limited conditions that were closer to more eutrophic habitats. The second experiment revealed divergent crisscrossing reaction norms in the developmental success of the sibling species in the two contrasted larval environments. As expected, An. coluzzii had higher emergence rates in the rice paddy environment with emerging adults of superior phenotypic quality compared to An. gambiae (s.s.), and vice versa, in the rain puddle environment. Conclusions Evidence for such G × E interactions lends support to the hypothesis that divergent larval adaptations to the environmental conditions found in man-made habitats such as rice fields in An. coluzzii may have been an important driver of its ecological speciation.

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