RESUMEN

Caliothrips phaseoli, a phytophagous insect, detects and responds to solar ultraviolet-B radiation (UV-B; lambda or= 400 nm) failed to elicit any response. All but six ommatidia of the thrips compound eye were highly fluorescent when exposed to UV-A of wavelengths longer than 330 nm. We hypothesized that the fluorescent compound acts as an internal filter, preventing radiation with lambda > 330 nm from reaching the photoreceptor cells. Calculations based on the putative filter transmittance and a visual pigment template of lambda(max) = 360 nm produced a sensitivity spectrum that was strikingly similar to the action spectrum of UV-induced behavioural response. These results suggest that specific UV-B vision in thrips is achieved by a standard UV-A photoreceptor and a sharp cut-off internal filter that blocks longer UV wavelengths in the majority of the ommatidia.

Asunto(s)

Insectos/fisiología , Insectos/efectos de la radiación , Rayos Ultravioleta , Animales , Conducta Animal/efectos de la radiación , Relación Dosis-Respuesta en la Radiación , Humanos , Dosis de Radiación , Luz Solar , Visión Ocular/efectos de la radiación

RESUMEN

Traditional chemically based methods for insect control have been shown to have serious limitations, and many alternative approaches have been developed and evaluated, including those based on the use of different types of mutation. The mutagenic action of ionizing radiation was well known in the field of genetics long before it was realized by entomologists that it might be used to induce dominant lethal mutations in insects, which, when released, could sterilize wild female insects. The use of radiation to induce dominant lethal mutations in the sterile insect technique (SIT) is now a major component of many large and successful programs for pest suppression and eradication. Adult insects, and their different developmental stages, differ in their sensitivity to the induction of dominant lethal mutations, and care has to be taken to identify the appropriate dose of radiation that produces the required level of sterility without impairing the overall fitness of the released insect. Sterility can also be introduced into populations through genetic mechanisms, including translocations, hybrid incompatibility, and inherited sterility in Lepidoptera. The latter phenomenon is due to the fact that this group of insects has holokinetic chromosomes. Specific types of mutations can also be used to make improvements to the SIT, especially for the development of strains for the production of only male insects for sterilization and release. These strains utilize male translocations and a variety of selectable mutations, either conditional or visible, so that at some stage of development, the males can be separated from the females. In one major insect pest, Ceratitis capitata, these strains are used routinely in large operational programs. This review summarizes these developments, including the possible future use of transgenic technology in pest control.

Asunto(s)

Genes de Insecto , Control de Insectos/métodos , Insectos/genética , Mutación , Animales , América Central , Cromosomas/genética , Cromosomas/metabolismo , Relación Dosis-Respuesta en la Radiación , Femenino , Humanos , Insectos/fisiología , Insectos/efectos de la radiación , Masculino , Modelos Genéticos , América del Norte , Esterilización Reproductiva

RESUMEN

Most of our present knowledge about the impacts of solar UVB radiation on terrestrial ecosystems comes from studies with plants. Recently, the effects of UVB on the growth and survival of consumer species have begun to receive attention, but very little is known about UVB impacts on animal behavior. Here we report that manipulations of the flux of solar UVB received by field-grown soybean crops had large and consistent effects on the density of the thrips (Caliothrips phaseoli, Thysanoptera: Thripidae) populations that invaded the canopies, as well as on the amount of leaf damage caused by the insects. Solar UVB strongly reduced thrips herbivory. Thrips not only preferred leaves from plants that were not exposed to solar UVB over leaves from UVB-exposed plants in laboratory and field choice experiments, but they also appeared to directly sense and avoid exposure to solar UVB. Additional choice experiments showed that soybean leaf consumption by the late-season soybean worm Anticarsia gemmatalis (Lepidoptera: Noctuidae) was much less intense in leaves with even slight symptoms of an early thrips attack than in undamaged leaves. These experiments suggest that phytophagous insects can present direct and indirect behavioral responses to solar UVB. The indirect responses are mediated by changes in the plant host that are induced by UVB and, possibly, by other insects whose behavior is affected by UVB.

Asunto(s)

Ecosistema , Insectos/fisiología , Luz Solar , Rayos Ultravioleta , Animales , Dieta , Insectos/efectos de la radiación , Lepidópteros/fisiología , Percepción , Plantas