There are sex-dependent differences in hematological and biochemical variables in adulthood attributed to the predominant effects of testosterone in males and estrogen in females. The Twin Testosterone Transfer (TTT) hypothesis proposes that opposite-sex females may develop male-typical traits due to exposure to relatively higher levels of prenatal testosterone than same-sex females. Additionally, prenatal testosterone exposure has been suggested as a correlate of current circulating testoste...
Abstract: Megathyrsus maximus is nonnative in the neotropics, with a tall form that is commonly used as a forage grass and a smaller-statured form that is considered invasive in south Texas, USA. Biological control researchers are challenged to find an agent that will attack the short form, but not the desirable tall form in other parts of the neotropics. We conducted molecular analyses on 155 Megathyrsus maximus samples from its native range in Africa and compared them with U.S. short-form ...
Abstract: Selection of oviposition substrate is critical in holometabolous insects. Female stable fies, Stomoxys calcitrans, locate and select vertebrate herbivore dung in which they lay their eggs. However, the preference for vertebrate herbivore dung by S. calcitrans females, its ftness consequences for ofspring,and the semiochemicals used to locate and select oviposition substrates remain unclear. Using oviposition choice tests and life table bioassays we found that gravid female S. calci...
Abstract: The Sokoke Scops Owl Otus ireneae is an East African endemic that occurs mainly in the Cynometra woodland of the Arabuko-Sokoke Forest (ASF) in coastal Kenya. Since its discovery in 1965 (Ripley 1966), two additional subpopulations were discovered; in 1992 a small population was discovered in the foothill forests of the east Usambara mountains in Tanzania (Evans et al. 1994),and in 2002 another small population was discovered in the Dakatcha woodlands, 30 km north of ASF (C Jackson...
Abstract: Background: Larviciding is an effective supplementary tool for malaria vector control, but the identification and accessibility of aquatic habitats impedes application. Dissemination of the insect growth regulator, pyriproxyfen (PPF), by gravid Anopheles might constitute a novel application strategy. This study aimed to explore the feasibility of using an attractive bait-station to contaminate gravid Anopheles gambiae sensu stricto with PPF and subsequently transfer PPF to larval h...
Abstract: The primary means of reducing malaria transmission is through reduction in longevity in days of the adult female stage of the Anopheles vector. However, assessing chronological age is limited to crude physiologic methods which categorize the females binomially as either very young (nulliparous) or not very young (parous). Yet the epidemiologically relevant reduction in life span falls within the latter category. Age-grading methods that delineate chronological age, using accurate m...
Abstract: Integrated vector management (IVM) is defined as "a rational decision-making process for the optimal use of resources for vector control" and includes five key elements: 1) evidence-based decision-making, 2) integrated approaches 3), collaboration within the health sector and with other sectors, 4) advocacy, social mobilization, and legislation, and 5) capacity-building. In 2004, the WHO adopted IVM globally for the control of all vector-borne diseases. Important recent progress ha...
Abstract: By choosing blood-carrying mosquitoes as prey, Evarcha culicivora, an East African salticid spider,specializes at feeding indirectly on vertebrate blood. It also has an exceptionally complex mate-choice system. An earlier study revealed that search-image use assists E. culicivora in finding prey and mates when restricted to using vision alone. Here we show that search-image use assists E. culicivora in finding prey and mates when restricted to using olfaction alone. After being pri...
Abstract: Despite prolonged interest in comparing brain size and behavioral proxies of “intelligence” across taxa, the adaptive and cognitive significance of brain size variation remains elusive. Central to this problem is the continued focus on hominid cognition as a benchmark and the assumption that behavioral complexity has a simple relationship with brain size. Although comparative studies of brain size have been criticized for not reflecting how evolution actually operates, and for ...
Abstract: Proficiency at planning is known to be part of the exceptionally complex predatory repertoire of Portia, a genus of jumping spiders (Salticidae) that specialize in preying on other spiders. This includes proficiency at choosing between two detour routes, with only one leading to otherwise inaccessible prey. Less is known about Portia’s proficiency at making strategic decisions pertaining to whether a detour is required or not. Using Portia africana, we investigated this by having...
Abstract: Males of Evarcha culicivora, an East African jumping spider (Salticidae), have bright red faces. Here, we investigated how seeing a red face might influence a male’s behaviour during encounters with another male. We applied black eyeliner to conceal the red on a male’s face and measured the spectral properties of male faces with and without the eyeliner. Only the faces without eyeliner reflected in the long-wavelength range corresponding to red. In experiments over 2 days, wher...
Abstract: The World Health Organization (WHO) predicts that the global population is expected to reach 9.8 billion in 2050 and projects growth mainly in global urban populations. The implications of this growth include changes in the urban environment, which will play an important role in public health, especially a significant proportion of global vector-borne tropical infectious diseases. Combined with these predicted developments is climate change and land use changes which will also grea...
Abstract: Previous research on Cyrba algerina (Araneae, Salticidae) has shown this jumping spider expresses predatory specialisation with respect to spiders as prey as well as inter-population variation in responsiveness to prey-spider odour. However, this earlier research pertained to a single prey species (Oecobius machadoi) and only field-collected C. algerina individuals were tested. Here we extend the previous research by using laboratory-reared, as well as field-collected, individuals ...
Abstract: Thermal adaptation is a key facet safeguarding organismal function among ectothermic organisms. In this era of rapidly changing environments, understanding the diverse mechanisms mediating organismal climate stress resistance have become a priority given contrasting efects on organisms, vis declines in keystone species and an increase in invasive pest species. Here, we review mechanisms and patterns of thermal adaptation among shifting climates, specifcally focusing on Lepidoptera,...
Abstract: Riverine tsetse (Glossina spp.) transmit Trypanosoma brucei gambiense which causes Gambian Human African Trypanosomiasis. Tiny Targets were developed for cost-effective riverine tsetse control, and comprise panels of insecticide-treated blue polyester fabric and black net that attract and kill tsetse. Versus typical blue polyesters, two putatively more attractive fabrics have been developed: Vestergaard ZeroFly blue, and violet. Violet was most attractive to savannah tsetse using l...