Roger E. Gold

Colony-level macronutrient regulation in ants: mechanisms, hoarding and associated costs

Social and nonsocial organisms both require a suite of nutrients in correct amounts and ratios to promote growth and fitness, but the nutrient profiles of available foods are rarely optimal. Nutrient acquisition in insect societies is more complex compared to that of nonsocial organisms however, because foraging is restricted to only a proportion of the colony, and these members must satisfy their own nutritional requirements and those of other members having distinct nutritional needs. In this study we used laboratory colonies of the fire ant Solenopsis invicta to quantify how ants regulate their protein–carbohydrate intake when restricted to diets with different fixed protein–carbohydrate (p:c) ratios, and to quantify, at both the individual and colony level, behaviours and costs associated with nutrient regulation when feeding on these foods. We found that ants were most attracted to foods with equal or moderately protein-biased p:c ratios. However, colonies on these two treatments created large hoards, and the p:c ratios of these foods differed from that of collected food. In general, carbohydrates were extracted and protein was retained. As a result, carbohydrate intake on all diets except the extremely protein-biased diet was similar. However, carbohydrate regulation on diets with equal and moderately protein-biased p:c ratios may be costly through elevated worker activity and mortality, and through reduction of worker lipid reserves. For colonies feeding on heavily protein-biased food, energy production may have been achieved via gluconeogenesis. We discuss our results in relation to how dietary p:c imbalances in naturally encountered foods may be driving ant foraging behaviour in the field. 2009 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Mitochondrial and Ribosomal Internal Transcribed Spacer 1 Diversity of Cimex lectularius (Hemiptera: Cimicidae)

Abstract Understanding genetic variation among populations of medically significant pest insects is important in studying insecticide resistance and insect dispersal. The bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), is widespread hematophagus insect pest around the world, including North America, and it has recently been identified as an emerging resurgent pest. To date, no studies have been conducted on genetic variation of this species. For this study, 136 adult bed bugs representing 22 sampled populations from nine U.S. states, Canada, and Australia were subjected to genetic analysis using polymerase chain reaction (PCR) to amplify and sequence a region of the mitochondrial DNA (mtDNA) 16S rRNA gene and a portion of the nuclear rRNA internal transcribed spacer (ITS) 1 region. For the 397-bp 16S marker, a 12 nucleotide sites in total were polymorphic, and 19 unique haplotypes were observed. Heterozygosity was observed within many of the sampled populations for the mtDNA marker. This suggests that bed bug populations did not undergo a genetic bottleneck as one would expect from insecticide control during the 1940s and 1950s, but instead, that populations may have been maintained on other hosts such as birds and bats. In contrast to the high amount of heterozygosity observed with the mitochondrial DNA marker, no genetic variation in the 589-bp nuclear rRNA marker was observed. This suggests increased gene flow of previously isolated bed bug populations in the United States, and given the absence of barriers to gene flow, the spread of insecticide resistance may be rapid.

Fabric Parameters and Pesticide Characteristics That Impact on Dermal Exposure of Applicators

Fabric functional finish and formulation of pesticides are factors that contribute to pesticide wicking, wetting, and penetration. Fluorocarbon soil-repellent finishes inhibit contamination of the fabric and of sentinel pads. An undergarment layer offers better protection than does a single layer. Spun-bonded olefin offers protection of the same magnitude as soil-repellent finishes. Methyl parathion residues after laundering were similar for the unfinished fabric, the durable-press finished fabric, and the soil-repellent finished fabric, but the initial contamination of the soil-repellent finished fabric was only 20% of that of the other two fabrics.

Detergents and water temperature as factors in methyl parathion removal from denim fabrics

ConclusionsBased on the results of this investigation, contaminated denim fabrics should not be laundered in 30°C (85°F) temperature; hotter temperatures are more effective. Although detergents could not be statistically separated, heavy duty liquid detergents appeared to excel in providing higher levels of pesticide removal in water temperatures of 49°C and 60°C. To determine the optimal conditions for pesticide removal by laundering, additional investigations need to be made into the relationships between detergent, pesticide formulation, water temperature, and effects of multiple washings.

Effect of Laundering Procedures and Functional Finishes on Removal of Insecticides Selected from Three Chemical Classes

Eleven pesticides from three chemical classes were chosen for comparison of residues after laundering. Pesticide was introduced to the fabric surface of one of three fabrics-unfinished (UN), renewable consumer applied fluorocarbon finished (RF), and commercially applied fluorocarbon finished (CM) fabric. The fabrics were laundered using one of three laundry treatments-a heavy-duty liquid detergent (HDL) alone, an HDL with a prewash spray, and an HDL with an agriculturally marketed pretreatment. Gas chromatographic analysis showed that the fluorocarbon-finished fabrics absorbed only 10% of the pesticide absorbed by the UN fabrics. Residues after laundering were significantly different both among and within classes. Although both fluorocarbon finishes reduced absorption of pesticide, they did not facilitate removal of the contaminant through laundering. Laundry additives significantly aided residue reduction.

Seasonality directs contrasting food collection behavior and nutrient regulation strategies in ants.

Long-lived animals, including social insects, often display seasonal shifts in foraging behavior. Foraging is ultimately a nutrient consumption exercise, but the effect of seasonality per se on changes in foraging behavior, particularly as it relates to nutrient regulation, is poorly understood. Here, we show that field-collected fire ant colonies, returned to the laboratory and maintained under identical photoperiod, temperature, and humidity regimes, and presented with experimental foods that had different protein (p) to carbohydrate (c) ratios, practice summer- and fall-specific foraging behaviors with respect to protein-carbohydrate regulation. Summer colonies increased the amount of food collected as the p:c ratio of their food became increasingly imbalanced, but fall colonies collected similar amounts of food regardless of the p:c ratio of their food. Choice experiments revealed that feeding was non-random, and that both fall and summer ants preferred carbohydrate-biased food. However, ants rarely ate all the food they collected, and their cached or discarded food always contained little carbohydrate relative to protein. From a nutrient regulation strategy, ants consumed most of the carbohydrate they collected, but regulated protein consumption to a similar level, regardless of season. We suggest that varied seasonal food collection behaviors and nutrient regulation strategies may be an adaptation that allows long-lived animals to meet current and future nutrient demands when nutrient-rich foods are abundant (e.g. spring and summer), and to conserve energy and be metabolically more efficient when nutritionally balanced foods are less abundant.

Laundry factors influencing methyl parathion removal from contaminated denim fabric

ConclusionsThe level of MeP concentration is inversely related to the amount of residue removed through laundry. As a result, higher pesticide concentrations or undiluted chemicals require utmost care in handling. Even following ten multiple launderings, residues of an undiluted MeP contaminant can be readily detected in fabrics, as well as cause mortality to German cockroaches within 24 h. It is recommended therefore, that clothing contaminated with high pesticide concentrations be disposed of by burning or burial, as the fabric remains unsafe to the wearer. Fabrics contaminated with lesser MeP concentrations (i.e. field strength) require a minimum of three launderings before biological activity reaches a harmless level. In addition, sudsy household ammonia as a laundry additive does not practically contribute to pesticide residue removal as the cost and amount of ammonia required to fill a washing machine is not feasible. Other laundry procedures, such as pre-rinsing and/or multiple washing, appear to be more effective.

Methyl parathion removal from Denim fabrics by selected laundry procedures

Safety is essential for persons working with pesticides because of the potential of health-endangering exposure. Reduction in pesticide-related accidents among these individuals requires knowledge of pesticide use, toxicology, and proper pesticide handling. WOLFE et al. (1967) established that the principal route of pesticide absorption into the body among agricultural workers was through the skin and not the respiratory system.

Genetic evidence for two introductions of the Formosan Subterranean Termite, Coptotermes formosanus (Isoptera: Rhinotermitidae), to the United States.

Abstract Exotic introductions of Formosan Subterranean Termite (FST) to the United States from Asia have had significant economic consequences. Multiple introductions through marine transport have been proposed, but identification of these routes has yet to reveal more than one lineage in the continental U.S. DNA sequencing of a 640-bp cytochrome oxidase II (COII) mitochondrial DNA (mtDNA) marker to 60 disjunct populations, revealed two independent lineages spanning the continental U.S., Hawaii, Japan, and China. Limited genetic variation was observed with this marker. Group I constitutes a largely Asian clade, while Group II is comprised of both Asian and southern U.S. populations. This is the first study which has documented 2 distinct lineages to continental United States and Hawaii.

Methyl parathion transfer from contaminated fabrics to subsequent laundry and to laundry equipment

ConclusionsBased on these data, the percentages of MeP transferred in laundry were miniscule; however care should be exercised in laundering of pesticide contaminated clothing in the home. WP formulations may be most easily removed from the original fabric and most readily transferred to the clean fabric due to the particulate nature of their composition. Rinsing the laundry apparatus is recommended even though subsequent work may reveal more satisfactory ways to effect equipment clean up. Although the percentage of pesticide transferred by contaminated laundry apparatus may be slight in relation to a.i. made available in laundry of contaminated clothing, this amount may affect particularly susceptible individuals. These conclusions were based on Laundry-Ometer studies and before other recommendations can be made, further field work should be undertaken using home laundry appliances.