Inhibitory potency increases several-fold when the glucosinolate alkyl chain gets longer , suggesting that PBITC, with its elongated alkyl chain compared to PEITC, may contribute an additional health benefit to this super food, although this remains to be proven. It is evident that watercress is particularly well-suited for indoor hydroponic growing systems, where plants exhibited the highest yielding leafy growth with improved nutritional profiles, ideal for consumer preferences. Altering the blue:red light ratio may further enhance the anti-cancer properties of this highly nutritious salad crop, but further studies are required to hone the light recipe for indoor cultivation. With climate change and increasing population density affecting the availability of typical fresh water supplies, it is important to look for new sources of water for agricultural irrigation. In arid California, over 750,000 acres of vegetables were harvested for fresh market in 2012 1 . Many of these vegetables are not drought tolerant plants and require frequent watering. As droughts become more frequent and water more scarce, there is a strong demand to use reclaimed and reused wastewater for irrigation purposes. Problematically, most wastewater increasingly contains pharmaceuticals and personal care products , mostly due to increased prescription rates with a growing population 2 . Currently, we do not know the effects most of these PPCPs have on crops or if they can bio-accumulate. The fear of contamination, primarily in raw vegetables,blueberry in pot by bio-accumulating of PPCPs has caused hesitance with respect to reclaimed water use in irrigation. Bio-accumulation and deposition of these PPCPs by sprinkler watering systems could also represent problems for Integrated Pest Management systems.

Most PPCPs originate from discharge from manufacturing companies, livestock farms, unaltered pharmaceuticals excreted from humans and livestock, and hospitals. Manufacturing and human-derived excretions go to wastewater treatment plants, which are only capable of removing a portion of all contaminants 3 . On many farms, manure from livestock treated with both growth hormones and veterinary antibiotics is used for fertilization without first being treated 4 . The continuous introduction and accumulation of anthropogenic contaminants has ultimately led to their presence in biologically active concentrations in the environment, including surface waters such as lakes and streams. PPCPs of major importance include: acetaminophen, caffeine; the steroidal hormones, 17α- ethynylestradiol, 17β- estradiol, estrone, 19-norethindrone; and the antibiotics lincomycin, oxytetracycline, and ciprofloxacin 5–7 . However, concentrations found in surface water are often much lower than concentrations present in wastewater effluents and field runoff, which can be as much as 5-100 times more concentrated 6,8. Several pharmaceuticals have been reported to cause physiological effects in a diversity of organisms ranging from the bottom to the top of the food web 9–13. For instance, the anti-inflammatory drug diclofenac was found to delay reproductive maturity in a freshwater crustacean, Daphnia magna, during a multi-generational study that used an environmentally relevant concentration of 0.36 µg/L 14. Antidepressants have been shown to reduce predator avoidance behaviors in fathead minnows, which has the potential to negatively impact population density 15. Estrogenic compounds were reported to disrupt mating behavior and secondary sexual characteristics in both fish and frogs 16–18. Similarly, permatogenesis and oocyte production were greatly hindered in alligators collected from a lake containing elevated xenoestrogen concentrations 19.

Chronic exposure to antibiotics has been found to cause significant decreases in stream detritivore biota and in other cases, increased antibiotic resistant gene expression in many microbiota, potentially leading to the development of resistant bacteria and pathogens.In Arabidopsis, antibiotics were shown to absorb through the roots and also to chelate calcium ions, thereby effecting gene expression and growth. Tetracyclines have also been shown to increase glutathione S-transferase activity in maze, but not in pinto beans, suggesting variability in plants’ susceptibility and/or ability to metabolize PPCPs. Wu and colleagues determined the concentration of nineteen PPCPs in six different vegetable crops grown hydroponically. The PPCPs were chosen to cover a wide range of chemical classes and the six crops cover the various types of vegetables that are eaten raw or with very little processing. These plants were grown in “spiked” nutrient solutions to remove the matrix effect of soil, which could accumulate certain contaminants, thereby slowly increasing concentrations of PPCPs. Wu et al. showed all nineteen contaminants can be absorbed depending on the plant and plant tissue in varying degrees. The highest concentrated PPCPs found in the tested plants were for the psycho-corrective drugs, carbamazepine and fluoxetine . However, there is no published study to date that has investigated the ability of plants to absorb and disperse antibiotics or hormones in a mixture, nor has there been any exploration into the impact these contaminants may have on critical insect-plant interactions or on insects’ endosymbionts that can influence nutrient acquisition, growth, and survival. Piercing insects, such as aphids, feed by sucking the phloem or xylem contents from plants, while many insects, such as the cabbage looper , consume whole leaves.

Chewing insects consume a variety of plant tissues which may sequester stored chemicals such as lipophilic and hydrophobic compounds. The effects of these instilled PPCPs could have physiological, multi-generational effects, and effect parasitoids’ ability to control insects. Many insects rely heavily on endosymbionts to live and grow. These endosymbionts subsist on nutrients provided by the host and in turn, they often make available nutrients the host is unable to produce or gain from its diet. This can be done by directly producing the nutrient or by breaking down plant products such as cellulose. Consequently, insects feeding on a contaminated diet that hinders endosymbionts would suffer from malnutrition resulting from decreased essential nutrient availability, leading to slow growth and development. Thus, insects feeding on contaminated plants could suffer from a decreased growth rate. Reduced rates of growth can lead to potentially greater exposure to pesticides, an increased period of exposure to parasites or predators during susceptible stages an inhibition of defenses against endoparasitoids , or increased exposure to induced plant defensive chemicals. Any of these effects could result in substantial changes in insect population development that affect insect control thresholds currently used to manage insect populations. Insects rely heavily on endogenous and external chemical signals for development, predator avoidance, mating, and oviposition preference. The endocrine system of insects produces several chemicals,plastic planters wholesale which bare striking resemblance to those of vertebrates, including humans. Some estrogenic- and androgenic-like substances have already been isolated in moths, Bombyx mori and Manduca sexta, beetles Tenebrio molitor, and flies, Sarcpohaga bullata . Exposure of insects to these chemically similar compounds is likely to disrupt normal functioning and development. The birth control agent, 17 α- ethynylestradiol , mimics 17β- estradiol and binds antagonistically to the estrogen receptors in mammals to produce its effects. EE2 has been shown to causes changes in mouthpart structure, development, oxidative-stress enzyme concentrations, and emergence of the non-biting midge, Chironomus riparius. Chemicals that do not resemble these structures, but bind to the receptors can also cause effects. In C. riparius, it was shown that Bisphenol A, a xenoestrogen and estrogen receptor antagonist, can bind and modulate the ecdysone receptor gene as it does for estrogen receptors in vertebrates, inducing an increase in ecdysone receptors. Bisphenol A has been shown to decrease vitellogenin in male C. riparius and at higher concentrations, reduces female vitellogenesis. Bio-accumulation of these chemicals has also been shown to increase in a dose dependent manner in members of the genus Chironomus . Terrestrial insects must search to find food sources and places suitable for reproduction, which leads to terrestrial insects expending energy to search and choose areas with the best resources possible; however insects are not always able to discern the best places to feed/ forage and reproduce.

Argentine ants do not avoid to the contaminant selenium in their diet, which can cause toxic effects from chronic ingestion. Contamination of pork liver with varying concentrations of female contraceptives, in a laboratory setting, effects up to three generations of the blow fly Chryrysoma megacephala. Effects of reduced and less developed ovarioles were not seen in the parent generation, facilitating the notion that contraceptive hormones and other chemicals’ effects may be passed on to offspring but show no effect in the parent generation. On the other hand, some PPCPs can hinder the parent generation, which would decrease the production of viable and reproductive progeny. For example, the female mealworm beetles, Tenebrio molitor, chose males treated with higher doses of atrazine, an estrogenic herbicide, more than males treated with lower doses. This would suggest that males can “lie” about how healthy they are by producing pheromones that entice females more . The same type of beetle, when injected with antibiotics, displayed an inhibited molting process and after ecdysis often displayed some pupal features. In tomato moths, , when either male or female moths were treated with testosterone, the pair produced not only smaller egg clutches but also less viable eggs. In all of these studies, the treatments were delivered in a way that removed any matrix effect of the chemical to the insect. The effects of PPCPs, matrices, plant defensive compounds, and insect-crop interactions are at the forefront of current research needs due to the increased demand for reclaimed wastewater. The goal of this dissertation is to generate novel insight into the effects PPCPs have on the ecology of insects across tropic levels, including insect microbial communities. My objectives include determining the effects of PPCPs on medically and economically relevant insects; determining the effects of PPCPs on insects’ microbial communities; and to determine if feeding style affects insects’ susceptibility to PPCPs.Use of pharmaceuticals and personal-care products has been increasing over the past 30 years, doubling or tripling in the past 12 years. Common PPCPs include, but are not limited to acetaminophen, mental stimulants, and treatments for heartburn, allergies, and bacterial infections. Since these products are excreted from the human body with little or no changes to the chemical structure , they frequently show up in wastewater treatment plants. Common wastewater treatment facilities are not equipped to remove all PPCPs and therefore discharge a wide range of concentrations into surface waters. Untreated water from treatment plants can be released into the environment during powerful storms, when the overflow drains directly into nearby aquatic systems . A study by Kolpin et al. found over 90 PPCPs in U.S. watersheds. In other countries, the concentrations of PPCPs in wastewater treatment plant effluents are even higher. In response to an increasing demand for fresh water, it has been proposed to use reclaimed wastewater for agricultural purposes 24. Unfortunately, PPCPs tend to be relatively longlived and mobile in both the soil and water. Therefore, runoff from agricultural fields irrigated with reclaimed water, or fertilized with reclaimed bio-solids, is likely to contain increased concentrations of PPCPs. There is minimal information available regarding the effects of PPCPs on insects in aquatic environments. However, some research has described PPCP effects on bacterial communities in aquatic environments and on aquatic plants. Kołodziejska et al. demonstrated that antibiotic contaminates commonly released from fisheries reducedgrowth of green algae and duckweed , as well as viability of the crustacean Daphnia magna. Rosi-Marshall et al. showed the stimulant, caffeine, significantly reduced respiration rates of stream biofilms, but had no effect on their bacterial composition. They also showed that an antihistamine, diphenhydramine, caused both a reduced respiration rate and a significant change in the bacterial community of the biofilms. These compounds were not designed or intended to affect bacterial communities. Thus, these variable impacts make predicting how chemicals will affect unintended target organisms difficult. PPCPs usually cause toxicity because they have similar chemical structures to an organism’s natural signaling compounds, resulting in expression or blockage of the organism’s receptors. For example, mammalian hormones, commonly used in birth control and hormone therapy, have been linked to endocrine disruption in reptiles, birds, and some arthropods. They also have been shown to alter primary and secondary sexual characteristics such as gonads and mating and courtships behaviors. Arthropods rely on various hormones for much of their coloration, production of eggs, mating behaviors, and immature development. While many insect hormones do not specifically match mammalian hormones, the structure of mammalian sex hormones and ecdysone are similar. In crustaceans, mammalian sex hormones have been shown to cause infertility, increase molting events, and inhibit chitobiase.