Host use by vectors is important in understanding the transmission of zoonotic diseases, which can affect humans, wildlife and domestic animals. Here, a synthesis of host exploitation patterns by kissing-bugs, vectors of Chagas disease, is presented. For this synthesis, an extensive literature review restricted to feeding sources analysed by precipitin tests was conducted. Modern tools from community ecology and multivariate statistics were used to determine patterns of segregation in host use. Rather than innate preferences for host species, host use by kissing-bugs is influenced by the habitats they colonise. One of the major limitations of studies on kissing-bug foraging has been the exclusive focus on the dominant vector species. We propose that expanding foraging studies to consider the community of vectors will substantially increase the understanding of Chagas disease transmission ecology. Our results indicate that host accessibility is a major factor that shapes the blood-foraging patterns of kissing-bugs. Therefore, from an applied perspective, measures that are directed at disrupting the contact between humans and kissing-bugs, such as housing improvement, are among the most desirable strategies for Chagas disease control.Key words: foraging -null models -diet analysis -multivariate statistics -Chagas disease -niche breadth Blood-feeding patterns of triatomines • Jorge Eduardo Rabinovich et al. 480 Several aspects of feeding-related behaviour in triatomines have also been well studied. Such aspects include feeding preferences (Quintal & Polanco 1977), avoidance of excessive warming during feeding (Lazzari et al. 2009), importance of nutritional status in flight initiation and dispersal (Lehane & Schofield 1982, Lehane et al. 1992, Noireau & Dujardin 2001, Emmanuelle-Machado et al. 2002, Ceballos et al. 2005, avoidance of predators during feeding (Bodin et al. 2009a, b), frequency and size of the blood intake (Maddrell 1963, Wood 1976, Montenegro & Pasina 1984, Maifrino et al. 1986, Pietrokovsky et al. 1996, Pereira et al. 1998, control of meal size (Bennet-Clark 1963b) and the relationship between feeding and defecation patterns as well as other aspects of feeding with epidemiological importance (Wood 1951, Dias 1956, Zeledón et al. 1970, 1977, Da Rocha e Silva et al. 1979, Crocco & Catalá 1996, Kollien & Schaub 1998, Zabala & D' Antonio 1988, Braga & Lima 1999, Aldana et al. 2001, Emmanuelle-Machado et al. 2002, Nattero et al. 2002, Almeida et al. 2003, Arévalo et al. 2007, Rodriguez et al. 2008, Klotz et al. 2009).Studies have been conducted on the relationship between the impacts of the triatomine feeding process and demographic parameters (Davies 1990, Malo et al. 1993, Emmanuelle-Machado et al. 2002, mortality and fecundity (Goodchild 1955, Hays 1965, Regis 1977, Patterson 1979, Catalá de Montenegro 1989, Braga et al. 1998, Braga & Lima 2001, Davey 2007, development time (Martinez-Ibarra et al. 2003, Martinez-Ibarra & Novelo-López 2004, resistance to starvation (Gajardo Tobar 1952,...

BackgroundOviposition-site choice is an essential component of the life history of all mosquito species. According to the oviposition-preference offspring-performance (P-P) hypothesis, if optimizing offspring performance and fitness ensures high overall reproductive fitness for a given species, the female should accurately assess details of the heterogeneous environment and lay her eggs preferentially in sites with conditions more suitable to offspring.MethodsWe empirically tested the P-P hypothesis using the mosquito species Aedes albopictus by artificially manipulating two habitat conditions: diet (measured as mg of food added to a container) and conspecific density (CD; number of pre-existing larvae of the same species). Immature development (larval mortality, development time to pupation and time to emergence) and fitness (measured as wing length) were monitored from first instar through adult emergence using a factorial experimental design over two ascending gradients of diet (2.0, 3.6, 7.2 and 20 mg food/300 ml water) and CD (0, 20, 40 and 80 larvae/300 ml water). Treatments that exerted the most contrasting values of larval performance were recreated in a second experiment consisting of single-female oviposition site selection assay.ResultsDevelopment time decreased as food concentration increased, except from 7.2 mg to 20.0 mg (Two-Way CR ANOVA Post-Hoc test, P > 0.1). Development time decreased also as conspecific density increased from zero to 80 larvae (Two-Way CR ANOVA Post-Hoc test, P < 0.5). Combined, these results support the role of density-dependent competition for resources as a limiting factor for mosquito larval performance. Oviposition assays indicated that female mosquitoes select for larval habitats with conspecifics and that larval density was more important than diet in driving selection for oviposition sites.ConclusionsThis study supports predictions of the P-P hypothesis and provides a mechanistic understanding of the underlying factors driving mosquito oviposition site selection.

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For bioremediation of organically enriched sediment deposited below fish farms, the extremely high potential for population growth of a deposit-feeding polychaete, Capitella sp. I, in the organically enriched sediment, and the effect on decomposition of organic matter in the sediment, were examined. A mass-culturing technique was conducted for this species. Bioremediation experiments were conducted on the organically enriched sediment in a fish farm in Kusuura Bay, Japan in 2003-2006. Approximately 1.7 million individuals of the worms were placed on the sediment below one net pen in December 2003, 9.3 million individuals in November 2004, and 2.2 million individuals in November 2005. After the worms were spread on the sediment, they rapidly increased in number and reached the highest densities of approximately 134 000 inds/m 2 in February 2004, 527 000 inds/m 2 in March 2005 and 103 000 inds/m 2 in January 2006.In the process of rapid population growth, the decomposition of the organic matter of the sediment was enhanced markedly. Our results demonstrate that the promotion of population growth by spreading cultured colonies of Capitella can enhance the decomposition rate of organic matter markedly in organically enriched sediment below fish farms. This method is promising for minimization of the negative effects of fish farms.

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