Insects require sterols for normal growth, metamorphosis, and reproduction, yet they are unable to synthesize these organic compounds and are therefore dependent upon a dietary source. For phloephagous species, such as Dendroctonus bark beetles, whose food does not necessarily contain appropriate types or adequate quantities of sterols, fungal symbionts may provide an alternative source in the form of ergosterol. We determined and compared the relative amounts of ergosterol in the primary fungal associates of Dendroctonus ponderosae Hopkins and Dendroctonus rufipennis Kirby. Ergosterol content of host tree phloem naturally infested with larvae (and their fungal symbionts) of both species also was compared with ergosterol contents in uninfested phloem tissue. Mycelia of Ophiostoma montium (Rumfold) von Arx and Ophiostoma clavigerum (Robinson-Jeffrey & Davidson) Harrington isolated from D. ponderosae mycangia, and Leptographium abietinum (Peck) Wingfield isolated from the exoskeleton of D. ruifpennis contained relatively large quantities of ergosterol, although no significant differences in content were found among these fungal species. Phloem colonized by larvae of both species contained significantly more ergosterol than did uninfested host phloem tissue. Our results suggest that larval life stages of D. ponderosae and D. rufipennis may obtain vital nutrients not only from the host tree phloem but also from fungal symbionts, in the form of ergosterol, while mining larval galleries.

The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is an introduced pest of unknown origin that is causing severe mortality to hemlocks (Tsuga spp.) in eastern North America. Adelgids also occur on other Tsuga species in western North America and East Asia, but these trees are not significantly damaged. The purpose of this study is to use molecular methods to clarify the relationship among hemlock adelgids worldwide and thereby determine the geographic origin of the introduction to eastern North America. Adelgids were collected from multiple locations in eastern and western North America, mainland China, Taiwan, and Japan, and 1521 bp of mitochondrial DNA was sequenced for each sample. Phylogenetic analyses suggest that the source of A. tsugae in eastern North America was likely a population of adelgids in southern Japan. A single haplotype was shared among all samples collected in eastern North America and samples collected in the natural range of T. sieboldii in southern Honshu, Japan. A separate adelgid mitochondrial lineage was found at higher elevations in the natural range of T. diversifolia. Adelgids from mainland China and Taiwan represent a lineage that is clearly diverged from insects in North America and Japan. In contrast to eastern North America, there is no conclusive evidence for a recent introduction of A. tsugae into western North America, where multiple haplotypes are found. Implications for hemlock woolly adelgid control, taxonomy, and plant–insect coevolution are discussed.

DNA barcoding involves the sequencing of a single gene region from all species to provide a means for identifying all of life. Although appealing to many scientists, this idea has caused considerable controversy among systematists. We applied a DNA barcoding approach to outbreak populations of invasive Liriomyza spp. leafminer pests in the Philippines to explore the use of barcoding in a relatively well studied, economically important group. We sequenced a 527-bp portion of mitochondrial cytochrome oxidase I (COI) from 258 leafminers from 26 plant host species in the Philippines. Neighbor-joining and parsimony analysis were used to compare COI sequences from the Philippines to an extensive database of COI sequences previously obtained from samples of the invasive leafminers Liriomyza huidobrensis (Blanchard), Liriomyza trifolii (Burgess), and Liriomyza sativae Blanchard from locations around the world. We conclude that although a DNA barcoding approach can provide rapid species identifications, in certain instances it is likely to either overestimate or underestimate the number of species present. Only when placed within the context of considerable other data can DNA barcoding be fully interpreted and used. For economically and medically important species, which can be well studied, DNA barcoding offers a powerful means for rapid identifications.

Xyleborus vochysiae n. sp. (Curculionidae: Scolytinae) is described and illustrated. This newly discovered ambrosia beetle was collected from live trees of Vochysia ferruginea Mart. in wet tropical forests of Costa Rica. The new species does not fit readily into either Ambrosiodmus or Xyleborus, but it is placed in the latter genus on the balance of the evidence; it is not obviously close to any Ambrosiodmus or Xyleborus in Central America. X. vochysiae is extraordinary in three regards: it is the largest Xyleborini found in the Neotropics, it has only been collected from live trees, and it seems to be restricted to only one host species. On a world basis, only five other ambrosia beetles are known that regularly breed in live trees, and no species are known that are as host specific as is X. vochysiae.

The sarcophagid flies that breed in North American pitcher plants of the genus Sarracenia are taxonomically revised and described. The species are as follows: Sarcophaga sarraceniae Riley, 1874; Fletcherimyia abdita Pape 1990; Fletcherimyia celarata (Aldrich, 1916); Fletcherimyia fletcheri (Aldrich, 1916); Fletcherimyia folkertsi Dahlem & Naczi sp. nov.; Fletcherimyia jonesi (Aldrich, 1916); Fletcherimyia oreophilae Dahlem & Naczi sp. nov.; Fletcherimyia papei Dahlem & Naczi sp. nov.; and Fletcherimyia rileyi (Aldrich, 1916). Life history information is provided, including host associations between the flies and pitcher plant species. Misidentifications and dubious identifications present in the literature are discussed. Literature reviews are provided for all species. Illustrations of the male and female genitalia should allow identification of all the included species. A key is provided to sort male specimens whose genitalia have not been spread.

Partial 18s rDNA sequences from 22 exemplar mayfly species (Ephemeroptera) representing 20 families were analyzed to obtain a best phylogenetic tree for comparison to previous phylogenetic hypotheses. With respect to relationships among the three major groupings, our molecular data support the hypothesis that Pisciforma and Setisura comprise a monophyletic sister group to the Furcatergalia, rather than the hypothesis that Setisura and Furcatergalia comprise a monophyletic group stemming from the Pisciforma. Within Pisciforma, acceptable trees show that Baetidae separates at the base of the Pisciforma clade. The data suggest that Pisciforma is paraphyletic and do not support the grouping of all Southern hemisphere families as a monophyletic group. An evolutionary sequence favored by the data suggests a grouping of Siphlonuridae, Rallidentidae, Nesameletidae, and Ameletidae and a grouping of Oniscigastridae, Ameletopsidae, and Acanthametropodidae. The data support the monophyly of Setisura (Heptageniidae, Arthropleidae, Pseudironidae, Oligoneuriidae, Isonychiidae, and Coloburiscidae). Within Setisura, a bootstrap/jackknife test places the families Heptageniidae, Arthropleidae, and Pseudironidae in one clade at 100% frequency. Also supported are hypotheses that Pseudironidae is a sister group to a Heptageniidae–Arthropleidae group and that a sister relationship exists between the latter two families. Hypotheses that Pseudironidae separated from other Setisura families at an earlier stage and comprises a sister group to a Heptageniidae–Oligonuriidae lineage or that Pseudironidae should be moved out of Setisura are not supported.

Indianmeal moth, Plodia interpunctella (Hübner), is one of the most important pests in retail stores and processed food facilities, but little is known about its ovipositional response to varying sizes and qualities of food sources. In this study, we monitored oviposition for 48 hours divided into 16 consecutive 3-h intervals, and found that, on average, P. interpunctella females laid eggs 6.4 times. We found a positive correlation between number of oviposition events and total oviposition. We conducted laboratory experiments to examine the distribution of eggs laid by P. interpunctella females in dishes that varied in size and number. Experiments were conducted with “improved” food (cracked or walnut oil-treated wheat kernels) and “control” food (plain untreated wheat kernels). In trials with dishes of two different sizes, P. interpunctella females seemed to distribute eggs according to the surface area of dishes regardless of the food. In trials with improved food, total oviposition was positively associated with the number of dishes, whereas the number of control dishes had no apparent effect on total oviposition. In trials with one improved food dish and one to eight control food dishes, P. interpunctella females consistently preferred oil-treated wheat kernels, whereas they showed no preference for cracked wheat kernels. Using an index of randomness (D_p), we demonstrated that the distribution of eggs was significantly different from a Poisson distribution, thus indicating that it was nonrandom, regardless of the number of dishes. Using an index of aggregation (I_m2), we showed that for all the foods, the distribution of eggs became increasingly aggregated with higher numbers of dishes and that this trend was most pronounced in trials with improved foods.

The fruit of indigenous, cultivated, and naturalized exotic plants was sampled in Kenya to determine the geographical and host plant distributions of the fruit fly pests Ceratitis anonae (Graham), Ceratitis cosyra (Walker), Ceratitis fasciventris (Bezzi), and Ceratitis rosa Karsch. In 1997, cultivated and wild fruit were sampled on the Kenya coast to determine seasonal patterns of host use by C. cosyra and C. rosa. From 1999 to 2004, the sampling effort was expanded to forested areas of the central and western highlands and to all fruit-infesting tephritids. Together, the four pest tephritid species were reared from 5.1% of 3,794 fruit collections, the latter making up 116 families and 882 species of host plants. C. anonae, C. cosyra, C. fasciventris, and C. rosa were reared throughout Kenya, from 14, 9, 30, and 28 plant species, respectively. Fifty-two of these plants represented previously unknown hosts for one or more of the tephritids. C. anonae was restricted to habitats west of the Gregory Rift Valley. C. fasciventris was found in western and central Kenya, but it was not reared from coastal fruit collections. C. rosa occurred at the coast and in central highland fruit. We provide evidence for the recent introduction of C. rosa into the central highlands. Only C. cosyra was found in habitats located in all three of the major regions sampled. Although distributed over a wider geographic area than the other species, C. cosyra had a markedly restricted host range. On the coast, C. cosyra used wild fruit, primarily Sclerocarya birrea (A. Rich.) Hochst. (Anacardiaceae), as hosts when mango was not fruiting. C. rosa was absent from our mango samples but attacked common guava and wild fruit species. Overall, C. anonae, C. fasciventris, and C. rosa had similar host profiles, but each also had unique hosts in which infestations were usually heavy. Members of the Sapotaceae and Annonaceae were the most important wild hosts of these three species. Within these families, host fruit were partitioned among these tephritid species and the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). The availability of wild host fruit, sometimes supplemented by naturalized invasive plants or cultivated fruit, provided for year-round breeding of C. anonae and C. fasciventris, whereas indigenous fruit were sufficient for breeding of C. rosa and C. cosyra during most of the year. Opiine braconids were reared from all four species of Ceratitis.

Dispersal of the southwestern corn borer, Diatraea grandiosella Dyar, was examined by release and recapture of dye-marked adults and by capture of feral adults in and around 50-ha center pivot irrigated fields of Bacillus thuringiensis (Bt) maize. Pheromone and blacklight traps were used to capture the adults. In 1999, 2000, and 2001, a total of 177, 602, and 1,292 marked males, and 87, 231, and 1,045 marked females were released in four irrigated Bt maize fields, respectively. Recapture beyond release point was 2.13, 6.17, 3.16, and 17.91% for males and 0, 0, 2.23, and 4.18% for females in the four fields, respectively. One male was recaptured over native vegetation outside the field perimeter, and one was caught in a neighboring maize field, 457 m from the release point. An exponential decay function explained recapture of marked adults across the dispersal distance. More than 90% of adults were recaptured within 300 m of the release point. Large numbers of feral adults were captured throughout the study fields and over native vegetation between fields. The feral adult dispersal could be described with a linear model. Virgin females (38% marked and 14% feral) were captured throughout the study fields. The recapture of marked insects suggests that the dispersal was limited. However, capture of feral adults throughout Bt maize fields indicates that the actual dispersal may be more extensive than indicated by recapture of marked adults. Potential refuge sources for the feral adults were 587–1,387 m from the edge of the fields. There seems to be some dispersal of D. grandiosella from the nontransgenic “refuge” fields into the transgenic fields, which may allow for some genetic mixing of the Bt-resistant and -susceptible insects to help suppress potential evolution of pest resistance to transgenic maize. However, it is not clear whether the dispersal recorded in this study is sufficient to support the current resistance management strategy for corn borers.

Cassida rubiginosa Müller (Coleoptera: Chrysomelidae) has attracted considerable interest as a potential biological control agent against thistle (Astaraceae: Cardueae) weeds, but population characteristics of this species are not well understood. We conducted an intensive mark–recapture study from 1996 to 1999 in Yuwaku, Kanazawa, Japan, to estimate adult population parameters such as population size, longevity, movement activity, reproductive rate, and winter survival. Overwintered adults began to emerge from hibernation in early April and actively moved among host plants until early May. Thereafter, adult dispersal activity decreased until late June, and the number of beetles gradually declined. New adults were active for only 2 to 3 wk after emergence and began aestivation at the end of August. Despite low reproductive rates per generation, the overwintering population was stable at a high density. Beetle longevity was substantial, and many individuals overwintered more than once. The age structure of adult beetles was responsible for the high stability of the population and low reproductive rate.

The critical photoperiod for diapause induction in the predator Geocoris uliginosus (Say) and the stage/instar(s) sensitive to diapause-inducing photoperiods were determined in the laboratory. Six photoperiods were used for the critical photoperiod experiment (all at 24 ± 1°C): 10:14, 11:13, 12:12, 13:11, 14:10, and 15:9 (L:D) h. The critical photoperiod was ≈13.2 h of light d⁻¹. At 12:12 and 11:13 h, 86–88% of the population entered diapause, whereas 20% or less entered diapause at longer daylength. To determine the stage/instar(s) sensitive to diapause-inducing photoperiods, cohorts of bugs were reciprocally switched between two photoperiods, 15:9 (not diapause-inducing) and 11:13 h (diapause-inducing), at the beginning of the second, third, fourth, and fifth instar, and at the beginning of the adult stage. A given cohort was switched only once during the experiment. Two additional cohorts were reared as controls under the respective photoperiods with no switching throughout the experiment. Exposure to diapause-inducing photoperiods from the beginning of the fifth instar through the adult stage induced reproductive diapause in 100% of the females in this experiment, whereas exposure from the beginning of the adult stage induced only 42% diapause. Thus, when daylength shortens to the critical photoperiod in late summer, most individuals that are in the nymphal stage will subsequently enter reproductive diapause, whereas a majority of those that have reached the adult stage by that date will reproduce.

The compatible interaction between virulent Hessian fly, Mayetiola destructor (Say), larvae and susceptible wheat, Triticum aestivum L., plants was investigated at the light microscope and ultrastructural levels. During the first day of larval attack at the base of the sheath of the third leaf of a wheat seedling, small punctures of the appropriate size (0.1 μm in diameter) and spacing of the paired larval mandibles were found in the outer wall of epidermal cells. Inside epidermal cells, nuclei and cytoplasmic organelles seemed to be breaking down, and the number and size of cytoplasmic vacuoles had increased. Two to 3 d later, epidermal and mesophyll cells at the base of the third leaf showed signs of becoming nutritive. Nutritive cells were identified by an increase in cytoplasmic staining, increased numbers of cellular organelles (mitochondria, proplastids, Golgi, and rough endoplasmic reticulum), numerous small vacuoles, and an irregularly shaped nucleus. The Hessian fly nutritive tissue probably acts as a sink tissue within the wheat seedling, benefiting the growth of larvae by importing photoassimilates. Breakdown of nutritive cells began soon after they were first observed, indicated by a change in the shape and density of the cell nucleus. Contents of nutritive cells moved through compromised cell walls into adjacent cells that had a more complete breakdown and loss of cytoplasm. Structural changes were not restricted to the third leaf. The sixth leaf, a leaf more recently initiated by the shoot apical meristem that was not directly fed upon by larvae, was found to consist primarily of well-developed epidermal layers, with poorly developed mesophyll cells. The implications of these findings for understanding incompatible interactions between avirulent Hessian fly larvae and R gene-defended plants are briefly discussed.

During research on the life history characteristics of insidious flower bug, Orius insidiosus (Say), fed soybean aphids, Aphis glycines Matsumura, the mouthparts of some predators were covered by a substance excreted from the cornicles of attacked aphids. The cornicle exudate was found to encumber both nymphs and adults of O. insidiosus causing death because of molting failure and starvation. Among predator stages, first instars were most severely affected. Feeding frequency affected the number of predators affected by the exudate, with predators fed more often having higher rates of exudate exposure and mortality. Soybean aphids produce exudate during all life stages, and its production does not seem to compromise the survival of the aphid. The exudate also seems to contain an alarm pheromone as evidenced by increased movement and activity of aphids in the vicinity of exudate-producing aphids. The potential impact of the aphid’s cornicle defenses on aphid–predator dynamics in soybean, Glycine max (L.) Merr., is discussed.

Preferences of female predators for various species of prey may not correlate with nutritional value of the prey, notably with regard to resulting rates of reproduction in the female predator. This study assessed the biochemical status of adult female Podisus maculiventris (Say) as affected by prey species. Colony-reared females were fed one of five species of natural or factitious prey: beet armyworm, Spodoptera exigua (Hübner); fall armyworm, Spodoptera frugiperda (J.E. Smith); cabbage looper, Trichoplusia ni (Hübner); wax moth, Galleria mellonella (L.); or yellow mealworm, Tenebrio molitor (L.). Fresh weights and contents of lipid, protein, and yolk protein were compared over periods of 7, 15, and 22 d. Fresh weights and protein showed no significant differences by trial length or by prey species. Total lipid content was the most significant parameter in relation to time and species of prey, ranging from 5.3 to 15.5% of mean fresh weight. Female P. maculiventris varied significantly in total lipid content by prey species at 15 and 22 d, and by week only when fed fall armyworm. Highest lipid contents were observed in females fed yellow mealworm, and lowest lipid contents were observed in females fed cabbage looper and beet armyworm. Yolk protein content did not correlate with cumulative oviposition, but it did vary with time in those females fed on the beet armyworm or the wax moth. Lipid content in female predators may vary inversely with reproductive potential or egg load and offers a quantitative measure of food quality.

Sexual dimorphism and the origin of conspicuous male characters in animals have been a major topic of evolutionary biology. Beetles (Coleoptera) possibly represent the greatest number and diversity of sexually dimorphic species. Yet, their features and the origin of oversized male apparatus are not fully understood. Morphological observations of 349 species and subspecies were used to describe the general features of sexual dimorphism and the development of outstanding male characters at the family, genus, species, and subspecies levels. Although allometrically developed male fighting apparatus is the most conspicuously sexually dimorphic, high male intraspecific variability and negatively allometric hind wings may be equally important biological features of sexually dimorphic beetle species. Male traits in sexually dimorphic species primarily evolved through positive allometry for larger apparatus. Their proportion to body size and actual size might have been further enhanced by concerted selection toward higher allometry and larger body, as evidenced by the highly significant interspecific correlation between the two traits seen within some existing genera. Yet, most oversized male traits may have evolved as a result of strong selection toward a larger body that in turn acts on the previously acquired allometry rather than by ongoing selection toward higher allometry. In some other genera, conspicuous male traits may be retained merely as an allometric inertia of selection toward larger body size even after the positive allometry ceased to be adaptively advantageous.

A data sample of 80 males and 43 females of the giant dynastine scarab Megasoma actaeon L. were analyzed with respect to scaling of the pronotum, elytra, and legs. In males, several somatic structures scale with nonisometry, and frontal and pronotal horns scale with very steep slopes to body length, whereas head width scales with negative allometry. This could indicate allocation of progressively more resources in major males to the sexually selected structures. In females, head width and the lengths of the first and third legs also scale with negative allometry to body size, whereas the depth of the abdomen scales with positive allometry. This could indicate allocation of progressively more resources in large females to reproduction. The huge size of M. actaeon notwithstanding, it would seem that it is more primitive in terms of sexually selected combat structures than equally large species of the closely related Chalcosoma Hope and Dynastes Kirby.

Results of Bayesian, maximum parsimony (MP), and neighbor joining (NJ) analysis of mitochondrial COII, 16S, and 12S gene DNA sequences and soldier morphology identified Chilean samples of a Reticulitermes species as the eastern subterranean termite, Reticulitermes flavipes (Kollar). All Chilean R. flavipes samples had identical gene sequences for all loci examined, suggesting a single geographic introduction. The combined DNA sequences for Reticulitermes santonensis Feytaud collected from France were almost identical to those of R. flavipes samples from Florida, which agreed with previous studies suggesting that R. santonensis is a junior synonym of R. flavipes. One unexpected finding was a R. flavipes sample collected from California that closely resembled the Chilean R. flavipes in their combined mitochondrial DNA sequences. We hypothesize that the Chilean R. flavipes may have been introduced from California or vice versa or that both Chilean and Californian R. flavipes may have the same origin in North America. Except for one sample from Florida (3% divergence), intraspecies variation of R. flavipes used in this study was <1%.

Theoretical and empirical studies of life history assume that egg size and number cannot be maximized simultaneously because of a trade-off between them. In many empirical studies, however, only egg size or egg number was examined as a fitness component of the mother. We estimated phenotypic and genetic correlations between egg size and number, and heritabilities of each trait by half-sib analysis in Callosobruchus chinensis (L.) (Coleoptera: Bruchidae). The signs of all genetic correlations between egg size and egg number were negative, but near zero and not significantly different from zero. The result means that no trade-off was found between egg size and egg number, at least in this beetle population. We discuss three reasons (i.e., laboratory adaptation, mutation, and resource acquisition ability) why we did not detect a significant negative genetic correlation between egg size and egg number even when genetic trade-off existed.

Ribosomal DNA sequence data has been important in elucidating molecular evolution, discerning phylogenetic relationships, and in developing species diagnostics. Species in the genus Anastrepha Schiner, particularly members of the Fraterculus Species Group, are considered the most important native pests of fruit in the New World. This study presents the first complete rDNA sequence data spanning the 5.8S to the internal transcribed spacer ITS2 of a species in this genus, Anastrepha suspensa (Loew). The GC content of the rDNA genes in A. suspensa was 50.8 to 40% for the 5.8S and 2S genes, respectively, but spacers were >84% AT rich. Spacer and gene lengths were of similar size to those found in other tephritids. Except for A. fraterculus s.l. (Wiedemann), spacers of other tephritid taxa were AT rich and contained numerous simple repeats. Sequence alignment with A. fraterculus s.l. indicated minor differences in the 5.8S rRNA gene, but the ITS2a was identical and the 2S gene differed by a single transition. The ITS2 of A. fraterculus s. l. was unusual in having a 41.7% GC content with three regions of C repeats. The ITS2 of A. suspensa had higher percent identity values with five species in other genera than it did with A. fraterculus s.l., suggesting an unusually high divergence rate in the latter.

Substrate-borne vibrations produced by adults of the treehopper Ennya chrysura Fairmaire (Hemiptera: Membracidae) on their host plant are described. Of eight different signals, five were produced by males, two by females, and one by both sexes. Possible functions are proposed according to the contexts in which signals were produced. As in other treehopper species, some vibrations were part of the courtship and probably also mate finding. Both sexes also produced signals when contacted by another individual. Females produced a drumming signal when contacted by a male or female and when rejecting a courting male; this signal was associated with aggressive behavior. Males produced a siren signal when contacted by a male or female and during certain portions of courtship songs of other males on the same plant. This signal was not associated with aggressive behavior and may serve to jam other males’ songs. This possible function has not been noted previously in any species that uses substrate-borne communication.

Mating compatibility among different populations of the South American fruit fly Anastrepha fraterculus (Wiedemann) was assessed through mating tests in pairwise combinations. Screened cages, inside a greenhouse, containing Citrus limon (L.) trees were used. Mating compatibility was determined using the index of sexual isolation. Most of the populations were noncompatible with each other and thus sexually isolated. Of these, Tucumán (Argentina) and Piracicaba (Brazil) populations showed a lower degree of isolation, whereas the other tested combinations were highly isolated. Full mating compatibility was detected only between two Argentinean (Concordia and Tucumán) and two Peruvian populations (La Molina and Piura La Molina). Flies were sexually active at different times: Tucumán, Concordia, and Piracicaba populations presented an early morning peak, La Molina and Piura La Molina were active around midday, and Ibague (Colombia) were active late in the afternoon. Manipulation of light phase conditions to match the times of maximum sexual activity did not increase the compatibility between La Molina and Tucumán. Based on these behavioral results, which confirm morphometric, genetic, and other evidence, the taxonomic revision of this cryptic species complex is warranted. One practical implication is that colonies of this pest to be used in any sterile insect technique approach should be derived from the target population or from a compatible population. Regional efforts should be initiated to determine the distribution of each subgroup and their relationship with each other in terms of compatibility.

In temperate climates, animals that produce long-term food caches must forage simultaneously for nutrients to survive, reproduce, and collect enough stores to survive the winter. Thus, an animal is simultaneously makes two foraging choices 1) what nutrients to collect for its immediate needs and 2) what food items should be stored. The cues the animal uses to make these two decisions should differ. This study examined the nutrient content of a seed-caching ant, Pheidole ceres (Wheeler) (Hymenoptera: Formicidae), to determine whether the nutrients found in stored seeds were different from the cues used to forage. The quantity of carbohydrates, lipids, amino acids, and proteins was measured in individual ants and seeds taken from eight P. ceres field colonies once a month from April to October. The relative nutrient levels were compared with the known foraging preferences of P. ceres at different times of the year. Seeds serve as the primary lipid and protein storage vessels, whereas the workers store amino acids and carbohydrates. The levels of carbohydrates and amino acids matched the foraging preferences for carbohydrates and proteins, respectively. This pattern suggests that the ants use nutrients that are not abundant in seeds as forging cues.