Sanford, Michelle Rene?e (2010-05). Associative Learning Capabilities of Adult Culex quinquefasciatus Say and Other Mosquitoes. Doctoral Dissertation. Thesis uri icon

abstract

  • The association of olfactory information with a resource is broadly known as olfactory-based associative learning. From an ecological perspective, associative learning can reduce search time for resources and fine tune responses to changing biotic and abiotic factors in a variable environment, which in mosquitoes has implications for pathogen transmission and vector control strategies. The purpose of this dissertation was to examine the ability for olfactory-based associative learning across the major life history domains of mosquitoes. Six different experiments comprise this dissertation. The first was to evaluate the response of mosquitoes following conditioning to 5, 10 or 50% sucrose concentrations with individual level mosquito conditioning and testing and introduction of statistical analysis with binary logistic regression. Mosquitoes did not respond in a dose dependent manner with respect to positive response to target odors following conditioning. This effect appears to be related to the mosquitoes' prior exposure to sugar as those exposed to 10% sucrose before conditioning did not prefer 50% sucrose but significantly fewer chose 5% sucrose. In an evaluation of host associated odors and second blood meal choice by females using a dual-choice olfactometer no significant effects were observed. The lack of significance may have been due to insufficient sample sizes, problems with odor collection or physiological state of mosquitoes. Effects of predatory mosquitofish on larval development and female oviposition choice were evaluated by rearing in separated habitats under three different treatments followed by an oviposition choice assay. Females did not prefer their natal habitat or avoid predators but chose substrate that had contained mosquitofish fed conspecific larvae. Mosquitofish affected larval development with acceleration in treatments with mosquitofish fed Tetramin(R) and delayed pupation in treatments with mosquitofish fed conspecific larvae. Mosquito memory length was evaluated by conditioning and testing at six time intervals from colony and field populations at two ages. Younger mosquitoes showed higher levels of positive response after conditioning at all time intervals except the longest (24h). Finally the olfactory-based associative learning ability of Anopheles cracens was evaluated. Significant evidence for learning was observed in males but not females at a memory length interval of 24h.
  • The association of olfactory information with a resource is broadly known as

    olfactory-based associative learning. From an ecological perspective, associative

    learning can reduce search time for resources and fine tune responses to changing biotic

    and abiotic factors in a variable environment, which in mosquitoes has implications for

    pathogen transmission and vector control strategies. The purpose of this dissertation was

    to examine the ability for olfactory-based associative learning across the major life

    history domains of mosquitoes.

    Six different experiments comprise this dissertation. The first was to evaluate the

    response of mosquitoes following conditioning to 5, 10 or 50% sucrose concentrations

    with individual level mosquito conditioning and testing and introduction of statistical

    analysis with binary logistic regression. Mosquitoes did not respond in a dose dependent

    manner with respect to positive response to target odors following conditioning. This

    effect appears to be related to the mosquitoes' prior exposure to sugar as those exposed

    to 10% sucrose before conditioning did not prefer 50% sucrose but significantly fewer chose 5% sucrose. In an evaluation of host associated odors and second blood meal

    choice by females using a dual-choice olfactometer no significant effects were observed.

    The lack of significance may have been due to insufficient sample sizes, problems with

    odor collection or physiological state of mosquitoes. Effects of predatory mosquitofish

    on larval development and female oviposition choice were evaluated by rearing in

    separated habitats under three different treatments followed by an oviposition choice

    assay. Females did not prefer their natal habitat or avoid predators but chose substrate

    that had contained mosquitofish fed conspecific larvae. Mosquitofish affected larval

    development with acceleration in treatments with mosquitofish fed Tetramin(R) and

    delayed pupation in treatments with mosquitofish fed conspecific larvae. Mosquito

    memory length was evaluated by conditioning and testing at six time intervals from

    colony and field populations at two ages. Younger mosquitoes showed higher levels of

    positive response after conditioning at all time intervals except the longest (24h). Finally

    the olfactory-based associative learning ability of Anopheles cracens was evaluated.

    Significant evidence for learning was observed in males but not females at a memory

    length interval of 24h.

publication date

  • May 2010