Ent. 105 Insects and people Senses lab Sounds Crickets 1. To what order does this insect belong? 2. Look at the wing dissection. Which wing has the file? 3. How does a cricket hear sounds? Where is its ear? 4. Observe the live crickets. Which are stridulating? a. nymphs b. teneral (unsclerotized) males c. mature males d. mature females 5. There are two containers, one which contains only males and one which contains both males and females. In which container is a larger percentage of males stridulating, all-male or mixedsexes? Patent leather beetles 1. To what order does this insect belong? 2. How does this species make sound? 3. Does this species produce sound --if exposed to a sudden bright light? --if exposed to a sudden loud sound? --if exposed to human breath? --when touched? Hissing cockroaches 1. To what order does this insect belong? 2. How does this species make sounds? 3. Do both sexes make sounds? 4. Under what circumstances does this insect make sounds? --if exposed to a sudden bright light? --if exposed to a sudden loud sound? --if exposed to human breath? --when touched? Grasshoppers 1. To what order does this insect belong? 2. How does this insect hear? 3. Where is the file on this insect? Cicadas 1. To what order does this insect belong? 2. Where are its sound-producing organs? 3. Do both sexes have sound-producing organs? Mosquitoes 1. To what order does this insect belong? 2. What do you notice about the antennae of male mosquitoes? 3. What do you think is the function of the male's antennae? Overall 1. In which of these insects do you think sound production is related to courtship? defense? courtship or defense? Why? Sights Light production in fireflies 1. Look at the specimens on display. Where are the light-producing organs? 2. Do both sexes have light-producing organs? Sexual dimorphism in tiger swallowtails 1. Look at the specimens on display. Which sex is dimorphic (occurs in more than one color form)? 2. Why do you suppose only one sex displays color polymorphism? Smells Saturniid moths 1. To what order does this insect belong? 2. What do you notice about the antennae of males? 3. What do you think is the function of the male's antennae? Pheromone traps Many pests of stored products, particularly beetles, produce aggregation pheromones to which both sexes respond. Presumably these pheromones help beetles that normally feed on widely spaced discrete food supplies to find each other and to find food. This behavioral response to a chemical signal has been exploited by people for detecting and controlling stored product pests. The The Pantry Pest Traptm for Indian meal moths is a “single-lure” system, which contains only sex pheromone. Compare this trap to the Japanese beetle trap. This particular trap is a so-called “dual-lure” system, which contains not only aggregation pheromone but also an attractant derived from the foods that Japanese beetles eat. Can you think of at least two reasons that a dual-lure system might be more useful than one containing only a pheromone or only a food attractant? In what ways would pheromone trapping be preferable to insecticide spraying to control stored product pests? Now look at the Mosquito Attractant trap. Knowing that the active ingredient, octenol, is a volatile chemical given off by large herbivorous mammals, would you expect more male or female mosquitoes attracted to this trap? American cockroaches Attractant pheromones can also be sex-specific, as is the case for many cockroach sex pheromones. Many cockroach sex pheromones have been identified and methods are in development to exploit these chemicals in traps and other devices for controlling cockroaches around kitchens and other places where food is handled. In this demonstration, a synthetic sex pheromone for the American cockroach, Periplaneta americanum (called bornyl acetate) has been obtained. Dip a glass rod in the solvent provided, allow it to dry and present it to a male American cockroach that has been isolated without females for at least four hours. What is his response to the rod? Repeat the procedure, but this time dip it into a solution of synthetic sex pheromone. Does the male respond differently to the glass rod now? Present the rod dipped in pheromone solution to a female cockroach isolated from males for at least four hours. What is her response? How does cockroach pheromone differ in its activity from flour beetle pheromone? If time permits, test the American cockroach pheromone analogue against other species of cockroaches. What can you conclude about the specificity of sex pheromones?