Banca de QUALIFICAÇÃO: JEAN PATRICK DA SILVA JORGE

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : JEAN PATRICK DA SILVA JORGE
DATA : 12/09/2019
HORA: 14:00
LOCAL: Sala de reuniões - DECOL
TÍTULO:

FEAR ECOLOGY: EFFECTS OF PREDATION RISK ON PREY BEHAVIOR, PHYSIOLOGY AND MORPHOLOGY: INTERACTION AMONG HABITAT PHYSICAL AND CHEMICAL FACTORS AND PREDATOR SPECIFIC RECOGNITION

PALAVRAS-CHAVES:

Responses anti-predation, oviposition habitat selection, trade-off, fitness, Lithobates catesbeianus, Aedes aegypti.

PÁGINAS: 50
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
RESUMO:

Natural selection tends to favor anti-predation strategies that minimize the risk of mortality and maximize individual and parental fitness, shaping responses that can be finely tuned to the environmental context, influenced by trade-offs. In aquatic ecosystems the detection and recognition of predators occurs mainly through chemical cues water-borne. Prey response to predation risk cues may be mediated by potentially interacting biotic and abiotic environmental factors that are still poorly understood. Organisms with complex life cycles, such as insects and amphibians, tend to be very responsive to predators or their cues, providing excellent models for studying processes that involve decision making and phenotypic plasticity as a function of predation risk. Oviposition habitat selection is one such process and plays a key role in population dynamics and community structuring. Despite its importance, there is still little knowledge about the behavior of gravid females searching oviposition sites in an environment varying in multiple factors of suitability for survival and development offspring. In the case of exotic species, conflicting situations in the presence of predators in the invaded environment are even more challenging. Native aquatic predators are one of the main barriers to the establishment of invasive species, contributing to the persistence of native species and community resistance. Thus, the degree of invasiveness and impacts generated on ecosystems invaded by exotic species depends on their ability to detect and respond to predator signals with which they did not co-evolve. There is still little knowledge about how exotic prey detect cues of native predators in the water and whether and how they respond through phenotypic adjustments that may impact ecosystem processes. In order to better understand these issues and contribute to the knowledge of the themes, two experiments were conducted corresponding to two ecological scenarios of predator-prey interactions. In the first (chapter 1), we tested the oviposition habitat selection behavior in Aedes aegypti under multivariate habitat suitability conditions. In a 2 × 2 × 2 factorial design, females were offered artificial containers with information on the presence or absence of (1) predation risk cues and (2) food addition, crisscrossing with two depth categories: shallow or deep habitat. Depth (P: F = 66.64, p = <0.0001) and Resource (S: F = 25.48, p = <0.0001) had a significant individual effect on the proportion of oviposited replicas per female. Predation risk alone had no significant individual effect on this response variable, but its effect was dependent on interaction with the Resource (R × S: F = 14.05, p = 0.0002). Depth (P: F = 58, p = <0.0001) and Resource (S: F = 20, p = <0.0001) had a significant individual effect in proportion to the total number of oviposited eggs per female. Again, the effect of Risk was dependent on the interaction with the Resource (R × S: F = 10, p = 0.002). The Depth × Resource interaction (P × S: F = 8, p = 0.005) had a significant effect on the proportion of the total number of oviposited eggs per female. These results suggest that Ae. Aegypti has the ability to evaluate and respond in order to avoid oviposition sites containing cues to predation risk, but in a complex way through trade-offs with the availability of feed for the offspring. Physicochemical factors of habitat suitability influence the survival and development of offspring in different ways and ovipositing females seem able to perceive and interpret the relative importance of each of them in a context-dependent manner, laying at least one egg at sites deemed appropriate and relying very further eggs in the most suitable, as predicted by the theory of fitness maximization. In the second scenario (chap. 2), the influence of a native predator (Belostoma sp.) on the behavior, physiology, morphology and stoichiometry of the invasive alien species Lithobates catesbeianus, the American bull frog, was evaluated. L. catesbeianus tadpoles were subjected to three treatments: (1) presence of caged predator and conspecific fed, (2) presence of caged predator and fish-fed, and (3) control without predator. Differences between control (3) and treatments (1) and (2) indicate that L. catesbeianus responds to predation risk. If the effects of treatments (1) and (2) are the same, this indicates that L. catesbeianus detects and responds to chemical signals water-borne that comes from the native predator itself and not from cues from the death of conspecifics. % of active individuals,% of aggregation and % of refuge use as behavioral parameters were analyzed; % of body N, P and C, N and P excretion rates, ratios C: P, C: N and N: P body and N: P excreta ratio as stoichiometric parameters; growth rate and final biomass as physiological parameters; and tail width, tail depth, tail length, body length and total length as morphological parameters. The ANOVA results show that there are no significant effects of treatments on the differences presented for all parameters analyzed. These results suggest that L. catesbeianus is a naive prey, which does not have the ability to detect cues of the native predator and therefore does not show plastic phenotypic responses to prevent predation. Despite being a successful invasive species its invasion success does not seem to depend on this ability. However, the analyzes presented here are not entirely adequate and present some misconceptions that may have influenced the results obtained. This points to a need for methodological reassessment of statistical analyzes.

MEMBROS DA BANCA:
Interno - 1714892 - ADRIANO CALIMAN FERREIRA DA SILVA
Presidente - 1434166 - LUCIANA SILVA CARNEIRO
Externo à Instituição - RAFAEL DETTOGNI GUARIENTO