Mission of CMAVE The Center conducts research aimed at reducing or eliminating the harm caused by insects to crops, stored products, livestock and humans. Research is directed not only at the insects themselves but at pathogens they may transmit and at identifying inherent protective mechanisms in plants.

Chemistry This Research Unit investigates the chemical, biochemical and physiological factors that regulate insect behavior and the interaction of insects with plants and other organisms in the environment

Chemistry Research Unit. Mission – investigates the chemical, biochemical and physiological factors that regulate insect behavior and the interaction of insects with plants and other organisms in the environment. Research Approaches – research focus is on identification, synthesis, biochemistry and behavioral analysis of semiochemicals that affect and influence insect behavior and physiology

Keys to Success. No single approach will result in effective control of a pest population. Ask simple questions. Know the system you are working in – know the insect inside and out. Dwell on your strengths develop effective collaborations to overcome weaknesses.

Insect Chemistry Research Unit: major project areas: Endogenous regulation of sexual maturity and sexual communication in pest insects.

Improving Efficacy of SIT by incorporation of Hormone and Dietary Supplements into Adult Holding Protocols

Males Require Several Days to Begin to Release Sex Pheromone or to Mate.

Mated Males Remated Much More Rapidly than did Virgin Males of the Same Age

Mated Females Released 2X More Pheromone

In the Tephritid Fruit Flies Both sexes require several days to become reproductively mature. This is similar to cockroaches and moths which have a period of reproductive diapause. In both moths and cockroaches Juvenile Hormone regulates reproductive development!

We Hypothesized that: Juvenile Hormone levels changed after mating. In young flies this resulted in improved sexual signaling and increased the probability that a male would mate. That Juvenile Hormone was the pivotal hormone regulating coordination of reproductive development with sexual signaling.

To Determine if Juvenile Hormone was involved we: Needed to identify JH from the blood of adult flies. Needed to show that JH levels were different in Mated and Virgin flies of the SAME age.

Two Juvenile Hormones have been Proposed to Function in Diptera Juvenile Hormone III is well documented to act in all insects.

We Identified Both JH III and JH III Bisepoxide from Hemolymph

Hemolymph from Mated Males Contained Significantly More JH than That from Virgins

We Applied Juvenoids Topically

Application of JH on Day 5 Induced Greater Pheromone Production on Day 6!

Application of Juvenile Hormone to Sterile Males Induced All Males to Mate Much Earlier.

Potential Use of Knowledge of Endocrine Regulation of Reproduction for Pest Control Improvement of Efficacy of SIT Programs. Incorporation of Analogs into Mass Rearing Programs or Release Protocols to Induce Sterile Males To undergo Accelerated Reproductive Maturity.

Improving Efficacy of SIT For Tephritids that require 7-12 days (Mexican, West Indian, Caribbean) to become sexually mature adding hormone to adult holding protocols is effective.

Hormone Therapy Will it be effective for Med Flies? The reason I ask is that Med Flies are not supposed to need 7-10 days to become sexually mature!

Hormone Therapy to Improve Efficacy of SIT for the Medfly!. Studies using the single sex strain of males from Guatemala. Females from the mixed sex strain in Guatemala. We thank the folks in Guatemala for support!

Effect of Topical Application of Hormone to Pupae 24h before Eclosion

Effect of Topical Application of Methoprene to Eclosed Adult Males on Calling

Two Day Old Male Medflies Released More Than Twice the Pheromone as Control Males Released

Treated Medflies Released Pheromone Earlier than Control Flies!

Feeding Methoprene to Flies Can we feed a water soluble formulation to adult flies and induce accelerated reproductive development?

Feeding Methoprene to Flies Methoprene used is a water soluble commercial formulation - “Nevweb igr 200” We are now testing a commercial formulation from Wellmark International and thank them for providing the formulation! Currently we incorporate 0.05% methoprene in diet.

Feeding Hormone to Males in the 3:1 Sugar:Protein Dry Diet Induced Males to Call Much Earlier.

Development of Delivery Technology with Caribbean Flies We began to assess delivery of hormone by incorporation of Methoprene, the JH mimic having the best overall activity, into AGAR-SUGAR food blocks. However, we encountered a significant problem with the AGAR-SUGAR diet in tests using the Caribbean Fruit Fly!

Flies Fed the AGAR Diet Were Much Less Attractive that Flies Fed the Dry Diet!

Diet Studies Clearly diet has an effect on Sexual Signaling by Male Caribbean Fruit Flies. Dry Diet Studies: Optimal Diet (3:1 Sugar to Protein Hydrolysate). What is important?

Dry Diet Study: Does Feeding Protein Increase Pheromone Release?

Dry Diet Study: Does Feeding Protein Improve Attraction?

Percent of Capture in Traps Emitting Pheromone from males fed Different Percents of Protein in Agar/Sugar blocks

Hormone Therapy to Improve Efficacy of SIT for Tephritid Fruit Flies (Now the Medfly!).

Med Flies Fed Agar Sugar Diet (Control Diet)

Addition of 10% Protein to Agar Sugar Diet

Effect of adding Hormone to Sugar Agar and Protein Diet

Effect of Hormone + Protein in Sugar Agar Diet on Female Capture

The Overall Benefits are Greater than the Sum of Each Improvement!

Insect Chemistry Research Unit: major project areas: Tritrophic interactions among insect herbivors, plants and insect predators/parasites.

Harnessing Plant Defenses Plants are capable of defending against insect herbivores and pathogens Direct and indirect defense can be formidable Understanding plant defensive mechanisms will lead to: More sustainable effective management of insect pests and pathogens The long range goal of our research on plant-insect and plant-pathogen interactions is to develop knowledge that can be used to devise practical, ecologically sound, sustainable pest management strategies for agriculture. To accomplish this we must understand the mechanisms, including chemical, biochemical and behavioral, that mediate the interactions of the plants and their attackers, as well as the natural enemies of the attackers, and that ultimately enable plants to successfully defend themselves against all the organisms that attack them.

When a plant is damaged by a feeding caterpillar the plant recognizes substances in the spit of the insect and turns on biochemical processes that produce both direct and indirect defenses. The major indirect defense consists of synthesizing and releasing volatile organic compounds that attract natural enemies of the caterpillars, such as the parasitic wasps that sting the caterpillars and deposit an egg. Natural enemies of insect pests of agriculture can be a powerful tool for biological control if they can be harnessed and used effectively.

This slide depicts the experimental design of screen cage tests to evaluate the female moths’ ability to discriminate between damaged and undamaged plants. On the right side of this slide female moths were given a choice between plants on one side of the screen cage that were all undamaged and plants on the other side of the cage, where two of the six plants were damaged by feeding caterpillars. The moths avoided all the plants on the side with damaged plants, preferring to oviposit on the side with all undamaged plants. The left side of this slide shows the experiment in which synthetic volatiles were formulated on rubber septa and placed in two of the six plants on one side of the cage. None of the plants in this experiment were damaged. The results of the experiment with synthetic compounds are shown in the next slide.

Damaged + Undamaged plants Time (%) Oviposition (%) 10 20 30 40 50 60 70 80 90 100 Time (%) 100 90 80 70 Oviposition (%) 60 50 40 30 20 10 Undamaged plants Damaged + Undamaged plants

White Mold on Peanut Plant We also recently discovered that peanut plants infected by the white mold fungus produce volatiles and that leaves of an infected plant are more palatable to beet armyworm larvae than leaves of a healthy plant. This suggests that the fungus is blocking the plant’s production of defensive chemicals that deter feeding by the caterpillars. The results of feeding experiments are shown in the next slide.

Feeding by Spodoptera exigua larvae on leaves from healthy and white mold-infected peanuts Leaf Area Consumed (%) Beet armyworm larvae were given a choice of a leaf of a healthy plant or a leaf of an infected plant. Both leaves were still attached to a plant and were caged together in a petri dish.

Insect Chemistry Research Unit: major project areas: Identification of new attractants for insect pests (Small Hive Beetle, Parasitoids, Tephritid Fruit Flies).

Isolation and Identification of the Pheromone of the Fruit Fly Parasitoid Diachasmimorpha longicaudata Female choice in yellow Multilure traps tested in a flight tunnel (n =3 )synthetic lures vs live males

Females are attracted to sweet Allysum a common garden plant. The Pheromone of Diachasmimorpha longicaudata may be important for monitoring but it is not really potent. Is there something better? Females are attracted to sweet Allysum a common garden plant. However, this plant does not occur naturally in the host range of the wasp! WHAT IS GOING ON?