Aphis craccivora Koch (Hemiptera: Aphididae) is an important pest of Lathyrus sativus L. plants, and causes retarded plant growth and loss of seed production. The insect sucks cell sap from flowers and lays nymphs on flowers. Hence, an attempt has been made to observe whether flower surface wax compounds (alkanes and free fatty acids) from two cultivars (BIO L 212 Ratan and Nirmal B-1) of L. sativus could act as short-range attractant and stimulant for nymph laying by adult viviparous females. The n-hexane extracts of flower surface waxes were analyzed by TLC, GC-MS and GC-FID analyses. Twenty one and 22 n-alkanes between n-C12 and n-C36 were detected in BIO L 212 Ratan and Nirmal B-1, respectively; whereas 12 free fatty acids between C12:0 and C22:0 were identified in both cultivars. Pentadecane and tridecanoic acid were predominant n-alkane and free fatty acid, respectively. One flower equivalent surface wax of both cultivars served as short-range attractant and stimulant for nymph laying through Y-tube choice experiments and I-tube viviparity assays, respectively, by adult viviparous females. A synthetic blend of nonacosane, tridecanoic acid and linoleic acid, and a synthetic blend of tetradecane, pentadecane, nonacosane, tridecanoic acid and linoleic acid resembling in amounts as present in one flower equivalent surface wax of BIO L 212 Ratan and Nirmal B-1, respectively, served as short-range attractant and stimulant for nymph laying by adult viviparous females. This study suggests that both these blends could be used in lures in the development of baited traps in pest management programmes.

Doryctobracon areolatus is a native parasitoid of the Neotropical region that presents the highest percentages of natural parasitism of fruit flies of the genus Anastrepha. In the Moscafrut Program SADER-SENASICA, located in Metapa de Domínguez, Chiapas, Mexico, a laboratory colony of this species is maintained on Anastrepha ludens, the Mexican fruit fly, with the aim to scale the production of the parasitoid up to massive levels. In order to eliminate unwanted emergence of adult flies during the rearing process, this study evaluated the effect of irradiation (at doses of 20, 30, 40, and 50 Gy) applied to eggs, and first and second instar larvae of A. ludens; all irradiated stages were subsequently exposed as second instar larvae to adult females of D. areolatus. Irradiation did not affect the eclosion of A. ludens eggs but, at doses of 40 and 50 Gy, it did cause delayed larval development and pupation, as well as lower larval weight. Adult fly emergence was suppressed at all doses, except in eggs irradiated at 20 Gy. Doses of 20 and 30 Gy applied to the eggs and larvae did not affect the emergence, survival, fecundity or flight ability of the emerged parasitoids, but the second instar larvae were easily handled during the rearing process. Our results suggest that D. areolatus can be successfully produced in second instar larvae of A. ludens irradiated at 30 Gy.

Macrolophus pygmaeus, a predatory mirid used to manage greenhouse whitefly, was illegally imported into New Zealand, and for a time was reared and sold to commercial tomato growers. We designed and implemented a risk-based detection survey to determine whether M. pygmaeus was still present in New Zealand a decade later. The survey was designed to have an 80% chance of detecting a single low density (0.05 per lineal metre of host plants) population within 1 km of known points of introduction. The survey was implemented between 8 and 15 March 2018. Local habitat constraints meant that the planned sampling had to be modified but this was accounted for in the subsequent analysis. No M. pygmaeus were found in the samples, but 93 specimens from seven other mirid taxa were detected, validating the sample methods. The survey gives 60% confidence that M. pygmaeus was not present at a mean density of 0.05 per lineal metre of habitat. It gives 80% confidence that a population at 0.1 m−1 was not present and 90% confidence that no population exists at >0.18 m−1. Though there are no published data on typical field population densities of M. pygmaeus, for related species the survey would have had high confidence in detecting any medium to high density population present. Therefore, it is likely that M. pygmaeus is no longer present in New Zealand, but if extant within the sampled areas then we have high certainty that it was at low densities compared to other predaceous mirids.

Four Beauveria bassiana and three Metarhizium brunneum isolates were evaluated, as soil drenches, against Spodoptera littoralis prepupae. Treatment efficacy was determined by assessing total mortality during development from prepupae through to pupae and adults; mortality and sub-lethal effects on reproduction were also quantified for adults emerging from surviving prepupae/pupae. All isolates were pathogenic but overall mortality varied between 31.7 and 83.3% (0% for control); average survival time was 7.5–10.5 days (14.0 days for control). From 1.7–15.0% of adults emerging from surviving prepupae/pupae were deformed (0% in control). Contact with fungal suspensions as prepupae/pupae caused a significant reduction in fecundity of emerging adult females (15–58.9%), and a significant reduction in egg viability (6.8–28.4%) compared with controls. Two isolates were selected for virulence evaluation against S. littoralis prepupae. The LC50s were 1.7 × 107 and 1.8 × 107 conidia ml−1 and the median survival times were 7 and 6 days for isolates EAMa 01/58-Su and EAMb 09/01-Su, respectively. Destruxin A was present in pupae developing from prepupae treated with isolates EAMa 01/58-Su (0.010 ± 0.002 µg pupae−1) and EAMb 09/01-Su (0.015 ± 0.003 µg pupae−1). The use of entomopathogenic fungi as soil drenches could be a key component of S. littoralis IPM strategies due to direct reductions in the number of soil-dwelling life stages and, also, the significant reduction in reproductive potential of surviving adults.

Helicoverpa zea (Boddie) is a damaging pest of many crops including soybean, Glycine max (L.), especially in the southern United States. Previous studies have concluded that oviposition and development of H. zea larvae mirror the phenology of soybean, with oviposition occurring during full bloom, younger larvae developing on blooms and leaves, intermediate aged larvae developing on varying tissue types, and older larvae developing on flowers and pods. In a field trial, we investigated the presence of natural infestations of H. zea larvae by instar in determinate and indeterminate soybean varieties. In complementary experiments, we artificially infested H. zea and allowed them to oviposit on plants within replicated cages (one with a determinate variety and two with an indeterminate variety). Plants were sampled weekly during the time larvae were present. In the natural infestation experiment, most larvae were found on blooms during R3 and were early to middle instars; by R4, most larvae were found on leaves and were middle to late instars. In contrast, in the cage study, most larvae were found on leaves regardless of soybean growth stage or larval stage. Determinate and indeterminate growth habit did not impact larval preference for different soybean tissue types. Our studies suggest H. zea larvae prefer specific tissue types, but also provide evidence that experimental design can influence the results. Finally, our finding of larval preference for leaves contrasts with findings from previous studies.

Flower and leaf herbivory might cause relevant and negative impacts on plant fitness. While flower removal or damage by florivores produces direct negative effects on plant fitness, folivores affect plant fitness by reducing resource allocation to reproduction. In this study, we examine the effects of both flower and leaf herbivory by leaf-cutting ants on the reproductive success of the shrub species Miconia nervosa (Smith) Triana (Family Melastomataceae) in a fragment of Atlantic Forest in Northeast Brazil. We conducted a randomized block-designed field experiment with nine replicates (blocks), in which three plants per block were assigned to one of the three following treatments: undamaged plants (ant exclusion), leaf-damaged plants (ant exclusion from reproductive organs, but not from leaves), and flower + leaf-damaged plants (no exclusion of ants). We then measured flower production, fruit set, and fruit production. Our results showed that flower + leaf-damaged plants reduced flower production nearly twofold in relation to undamaged plants, while flower set in leaf-damaged plants remained constant. The number of flowers that turned into fruits (i.e., fruit set), however, increased by 15% in flower + leaf-damaged plants, while it slightly decreased in leaf-damaged compared to undamaged plants. Contrastingly, fruit production was similar between all treatments. Taken together, our results suggest a prominent role of ant floral herbivory across different stages of the reproductive cycle in M. nervosa, with no consequences on final fruit production. The tolerance of M. nervosa to leaf-cutting ant herbivory might explain its high abundance in human-modified landscapes where leaf-cutting ants are hyper-abundant.

Telenomus podisi Ashmead (Hymenoptera: Scelionidae) is the most important egg parasitoid of Euschistus heros (Fabricius) (Hemiptera: Pentatomidae), and its successful parasitism is related to their searching ability to find suitable hosts under a complex chemical environment using host-reliable cues. Thus, the objective of this study was to elucidate chemical substances on the external layer of E. heros eggs and report its potential kairomonal activity on T. podisi. We tested female wasps in olfactometer system to synthetic compounds obtained from a chemical identification of E. heros egg masses. The synthetic blend was also evaluated in parasitism tests under laboratory and semi-field conditions. We identified 31 substances from egg surface extracts, including monoterpenes, aldehydes and alkanes. Among those compounds, a synthetic solution including camphene, β-pinene, limonene and benzaldehyde-induced chemotaxic behaviour on the wasps and increased the parasitism on E. heros eggs, either in laboratory or semi-field test, suggesting its potential use to T. podisi manipulation and parasitism improvement.

Irradiation is a physical, environmentally friendly treatment which does not leave any residues in the product. It is increasingly used as an alternative to methyl bromide and other chemical fumigants for disinfestation of insect pest in stored grains. In this research, we try to evaluate the effect of low gamma irradiation doses in the range of 50–1200 Gy on the different stages of Callosobruchus maculatus. It was found that no adults emerged after irradiation of eggs at 450 Gy. No emerging adults (F1 generation) have been shown when larvae or pupae were exposed to 650 Gy. Also, no emerging adult has been shown from the parental C. maculatus adults irradiated with 650 Gy. When suppression of F1 generation was used for the measuring effective irradiation dose and phytosanitary efficacy, 650 Gy was required for disinfestation of cowpea seed weevils. The irradiation dose level of 650 Gy was used for the large-scale confirmatory tests applied to 27,754 adults of C. maculatus in cowpea seeds resulting in non F1 adults' production with a confidence level of 93.77%. All the physical and chemical characteristics of cowpea seeds were non-significantly (P ≤ 0.05) affected by the irradiation dose of 650 Gy. Meanwhile, this irradiation dose very slightly reduced the microbial load of cowpea seeds. We recommend the generic dose 650 Gy as the phytosanitary irradiation dose for the cowpea seed weevil.

The effect of structurally related sesquiterpenoids (E,E)-farnesol and cis-nerolidol on the host-plant selection behaviour of the peach potato aphid Myzus persicae (Sulz.) was evaluated using electrical penetration graph (EPG) technique. No repellent effects of (E,E)-farnesol and (Z)-nerolidol to M. persicae were found but aphid probing activities on (E,E)-farnesol- and cis-nerolidol-treated plants were restrained. During non-phloem phases of probing, neither (E,E)-farnesol nor (Z)-nerolidol affected the cell puncture activity. On (E,E)-farnesol-treated plants, the total duration of phloem phase, the mean duration of individual sustained ingestion periods were significantly lower, and the proportion of phloem salivation was higher than on control plants. On (Z)-nerolidol-treated plants, the occurrence of the first phloem phase was delayed, and the frequency of the phloem phase was lower than on control plants. The freely moving aphids were reluctant to remain on (E,E)-farnesol- and (Z)-nerolidol-treated leaves for at least 24 h after exposure. (E,E)-Farnesol and (Z)-nerolidol show complementary deterrent properties, (E,E)-farnesol showing ingestive and post-ingestive activities and nerolidol showing pre-ingestive, ingestive, and post-ingestive deterrent activities.

Triatoma infestans (Klug) (Hemiptera: Reduviidae) is the main vector of Chagas disease in the Southern Cone of America and resistance to pyrethroid insecticides has been detected in several areas from its geographical distribution. Pyrethroid resistance presents a complex geographical pattern at different spatial scales. However, it is still unknown if the toxicological variability is a common feature within villages of the Gran Chaco were high resistance was descripted. The objectives of this study were to determine: (a) the microgeographical distribution of the deltamethrin-resistance in insects from Pampa Argentina village, (b) the performance of the insecticide impregnated paper bioassay to evaluate deltamethrin-resistance in field collected insects and (c) the lethal activity of the fumigant canister containing DDVP against insects resistant to deltamethrin. High survival of T. infestans exposed to discriminant dose was observed in the samples of all the evaluated dwellings, suggesting that the resistance to deltamethrin is homogeneous at the microgeographical level. Resistance determination by impregnated paper bioassay was similar to traditional topical determination, highlighting the use of this rapid methodology in field large-scale monitoring. The fumigant canister was not effective against resistant insects, remarking the need to develop suitable formulations that ensure minimal toxicological risk and high effectivity.

Four putative knockdown resistance (kdr) mutations have been documented in the voltage-gated sodium channel (VGSC) gene of Cimex hemipterus from several countries. However, no information regarding kdr mutations in any Chinese tropical bed bug population is available to date. In this study, a double-mutation（M918I + L1014F）kdr allele was identified in six C. hemipterus populations across Guangxi Zhuang Autonomous Region of China. The frequency of this allele was 100% in all the six examined populations. In addition, only two cytochrome c oxidase I (COI) gene haplotypes, with one synonymous nucleotide variation, were identified in a total of 48 individuals from six locations. The fixation and broad geographic distribution of this resistant allele questions the continued use of pyrethroids in the treatment of tropical bed bug infestations. The very low genetic diversity within and among these populations indicates that these bed bugs may have a single origin.

In Western Burkina Faso, the host range of fruit flies was evaluated in three plant formations between May 2017 and April 2019. Samples of 61 potential hosts were collected and incubated for fruit fly emergence. Twenty-seven hosts including cultivated and wild fruit were identified. Among cultivated fruit species, mango, and guava were the most infested while high infestation incidences were observed in the fruit of the indigenous plants Vitellaria paradoxa, Annona senegalensis, Sarcocephalus latifolius, and Saba senegalensis. Low infestation rates were observed in Anacardium occidentale, Citrus species, Opilia celtidifolia, and Cissus populnea. The highest infestation index (1648.57 flies kg−1) was observed from V. paradoxa. Eleven new host fruit infested with many fruit fly species are reported in Burkina Faso. A total of 18 fruit fly species were reared; Bactrocera dorsalis (42.94%), Ceratitis cosyra (29.93%), and Ceratitis silvestrii (22.33%) dominated those that emerged. Four fruit fly species have been detected for the first time in Burkina Faso. The main suitable fruit hosts are abundant and available from May through August during the rainy season and become rare and have low infestation from November to April during the dry season. This is the first study of its kind in the region. This study shows that the three plant formations had an impact on population dynamics of the three tephritid species of economic importance in Western Burkina Faso. This information should be integrated into the development of a fruit fly pests management strategy.

Entomological indicators such as vector density, distribution, biology and bionomics and their vectorial attributes are important parameters for measuring the pattern and intensity of malaria transmission. Although published articles provide evidence for the existence of associations between entomological indices and malaria transmission dynamics, none of them is able to establish a strong correlation. In order to address this issue, the present study aims to assess how malaria transmission is influenced and can be predicted by local major vector dynamics. We carried out an entomological assessment of major Anopheline vector abundance, habit/habitat, resting and feeding behavior, infectivity rates, and other entomological parameters. Results suggest that malaria transmission was correlated with a vector control intervention and non-intervention scenario in a high endemic region of Kalahandi district of Odisha, India. Amongst all indices, infective anthropophagic vectors established a strong positive correlation with malaria morbidity in comparison to infective or anthropophagic vector species during both the study periods. Though other entomological parameters influenced the transmission intensity, little quantifiable association was detected among study sites. This study provides strong baseline evidence of an association between entomological indices and malaria transmission dynamics, which could be used as an early warning system for outbreak prediction.

Spodoptera exigua Hübner and Sesamia cretica Led. (Lep., Noctuidae) are two important pests of corn. In this study, the effect of weed bands in the corn field, as weedy culture, on population density and damages of the pests were evaluated during two growing seasons (2016/2017). Cumulative insect days (CID) of each lepidopteran pest in weedy culture were compared with non-weedy culture. Results showed that CIDs of S. exigua and S. cretica in the non-weedy corn culture were significantly higher than the weedy corn culture. There was no significant difference between the total yield in the weedy and non-weedy cultures. Also, determinations of spatial distributions of the pests in the weedy and no-weedy treatments using Taylor's power law (TPL) and Iwao's patchiness (IP) showed that TPL provides a better fit for the data than IP and spatial distributions of both pests on both cultures were aggregative. Moreover, minor differences were observed between spatial distribution parameters of the pests in the weedy and non-weedy cultures. Green's model was used for developing a fixed-precision sequential sampling plan of the pests on the weedy and no-weedy treatments. Optimum sample sizes of S. exigua ranged from 532 to 5370 and 428 to 5296 plants and S. cretica varied from 297 to 2040 and 43 to 186 plants in the non-weedy and weedy cultures based on the desired precision level (0.25–0.1). Estimated stop lines of non-weedy and weedy cultures for S. exigua ranged from 0.000057 to 52.59 and 0.00029 to 58.87 and for S. cretica ranged from 1.59 to 111.5 and 2.09 to 98.03 larval cumulative numbers, respectively (0.25–0.1). The performance of the sampling plan was validated by resampling analysis using RVSP software. Results of the study can be used in the integrated pest management program of corn fields.

Insecticide resistance is an increasing problem in citrus production. The Asian citrus psyllid, Diaphornia citri Kuwayama, is recognized as one of the most important citrus pests worldwide and it has developed resistance in areas where insecticides have been overused. The development of insecticide resistance is often associated with fitness costs that only become apparent in the absence of selection pressure. Here, the fitness costs associated with resistance to thiamethoxam and imidacloprid were investigated in three agricultural populations of D. citri as compared with susceptible laboratory colonies. Results showed that all field populations had greater resistance than laboratory susceptible colonies. For both thiamethoxam and imidacloprid, a Candidatus Liberibacter asiaticus-positive (CLas+) colony was more susceptible than the CLas− colony. Resistance ratios ranged from 7.65–16.11 for imidacloprid and 26.79–49.09 for thiamethoxam in field populations as compared with a susceptible, CLas− laboratory strain. Among three resistant field populations, a significantly reduced net reproductive rate and finite rate of population increase were observed in a population from Lake Wales, FL as compared to both susceptible strains. The fecundity of field populations from Lake Wales, FL was statistically lower than both laboratory susceptible populations. Certain changes in morphological characteristics were observed among resistant, as compared, with susceptible strains. Our data suggest fitness disadvantages associated with insecticide resistance in D. citri are related to both development and reproduction. The lower fitness of D. citri populations that exhibit resistance to neonicotinoid insecticides should promote recovery of sensitivity when those populations are no longer exposed to thiamethoxam and/or imidacloprid in the field. The results are congruent with a strategy of insecticide rotation for resistance management.

Diamides have been used worldwide to manage the diamondback moth (DBM), Plutella xylostella L. (Lepidoptera: Plutellidae), however some strains showed resistance to these molecules. Also, pheromone traps could be used to manage this pest, hence reducing the use of insecticides in the field. Resistant DBM strains may have biological disadvantages in comparison to susceptible strains in areas without sprays, including reduction in fitness or behavioral changes. Therefore, the aim of this study was to investigate whether DBM strains resistant to chlorantraniliprole showed adaptive costs that could alter male attraction to the sex pheromone, in comparison to susceptible strains in the laboratory and semi-field conditions. First, the LC1, LC10, LC25, and LC50 of DBM to chlorantraniliprole were established, which were 0.003, 0.005, 0.007, and 0.011 mg a.i. liter−1, and 5.88, 24.80, 57.22, and 144.87 mg a.i. liter−1 for the susceptible and resistant strains, respectively. Development and reproduction of DBM strains subjected to those concentrations were compared. Later, male response to the sex pheromone was investigated in a Y-tube in the laboratory and in a greenhouse to pheromone traps. Resistant DBM strain showed an adaptive cost in comparison to the susceptible strain that can result in a delay in population growth in the field when selection pressure is absent. Conversely, resistant males have no olfactory response alteration in comparison to susceptible males, consistently at 3 (P = 0.6848) and 7 days (P = 0.9140) after release, suggesting that pheromone traps continue to be a viable alternative to manage DBM in an IPM system.

Species of Agonoscena (Hemiptera: Aphalaridae) are key pests of pistachio in all of the most important pistachio producing countries in the Old World. The efficiency and accuracy of DNA barcoding for the identification of Agonoscena species were tested using mitochondrial cytochrome c oxidase subunit 1 (mtCO1) and cytochrome b (cytb) gene sequences. Moreover, morphometric sexual dimorphism was studied. Finally, the potential geographical distribution of Agonoscena pistaciae, the most important pistachio pest, was calculated using the MaxEnt model. Similar relationships of clustering were found in the morphometric analysis and the molecular analyses with mtCO1 and cytb genes, with A. bimaculata and A. pistaciae being closely related, and A. pegani constituting their sister group. Although the results showed that the cytb gene is a better marker for barcoding in this group, the mtCO1 gene clearly separates the three psyllid species making mtCO1 suitable for diagnostic purposes. A geometric morphometric analysis showed that the distance between landmark number 7 (bifurcation of vein M) to the fore margin of the forewing, and the distance between landmarks number 6 (apex of vein Cu1b) and 11 (wing base), are the most important geometric characters for diagnosing the studied species. Moreover, the forewing shape of males vs females is similar in A. pistaciae and A. bimaculata but differs significantly in A. pegani. In the ecological niche modeling of the distribution of A. pistaciae, the most important contribution was made by the variable ‘minimum temperature of coldest period’. The most suitable areas for A. pistaciae are restricted to Eastern, Southern and some parts of Central Iran.

Panonychus citri (McGregor) is the most common pest in citrus-producing regions. Special low-toxicity acaricides, such as spirocyclic tetronic acids and mite growth inhibitors, have been used for a long time in China. However, pesticide resistance in mites is a growing problem due to the lack of new acaricide development. Wide-spectrum insecticides, such as amitraz have gained acceptance among fruit growers. An amitraz-resistant strain of P. citri was obtained by indoor screening to examine field resistance monitoring of mites to acaricides and to explore the resistant mechanism of mites against amitraz. The amitraz-resistant strain of P. citri had an LC50 value of 2361.45 mg l−1. The resistance ratio was 81.35 times higher in the resistant strain of P. citri compared with the sensitive strain. Crossing experiments between the sensitive and resistant strains of P. citri were conducted, resulting in a D value of 0.11 for F1 SS♀×RS♂ and 0.06 for F1 RS♀×SS♂. Reciprocal cross experiments showed that the dose–mortality curves for the F1 generations coincided, indicating that the resistance trait was not affected by cytoplasmic inheritance. The dose–expected response relationship was evaluated in the backcross generation and a significant difference was observed compared with the actual value. The above results indicate that the inheritance of resistance trait was incompletely dominant, governed by polygenes on the chromosome. Synergism studies demonstrated that cytochrome P450s and esterase may play important roles in the detoxification of amitraz. Based on differential gene analysis, 23 metabolism-related genes of P. citri were identified, consistent with the results of synergism studies. Real-time PCR verification implied that P450s, ABC transporters, and acetylcholinesterase might influence the detoxification of amitraz by P. citri. These results provide the genetic and molecular foundation for the management of pest mite resistance.

Elaeidobius kamerunicus Faust (Coleoptera, Curculionidae) is one of the specific pollinators on inflorescences of the African oil palm Elaeis guineensis Jacquin. This derelomine weevil is native to tropical Africa. During the late 20th century, it was introduced into all tropical regions where E. guineensis is grown, in order to improve its pollination and fruit set. Despite an overall success, a decline in pollination efficiency has been documented in several regions. In this study, we reconstructed a multilocus phylogeography of the world populations of E. kamerunicus, in order to explore its genetic diversity in its native and introduced ranges. Our results showed that African populations of E. kamerunicus are forming two differentiated mitochondrial clusters in West and central Africa, forming a contact zone along the Cameroon Volcanic Line. The existence of this sharp contact zone along this weak altitudinal barrier suggests that other parameters, such as climate, may be driving the distribution of populations. A differential genetic structure between mitochondrial and nuclear genes, and the strong level of genetic structure of the mitochondrial gene, also suggest sex-biased dispersal in this species, with males dispersing more than females. The genetic structure inferred from Asian and South American populations suggests that they originate from populations of both western and central tropical Africa and that a bottleneck has probably been experienced by these populations.

Body size is an important life-history trait in eusocial insects which plays a key role in colony fitness. The division of labour, represented by caste polyethism, correlates with divergent morphological traits. Size polymorphism has been noted in the tropical fire ant, Solenopsis geminata; however, little is known regarding the differences in the size distributions of workers performing foraging tasks. In the present study, task partitioning was observed in the foraging activities of S. geminata. Two subgroups among foraging workers of S. geminata were discovered using the Gaussian mixture model: a large worker group (head width ≥ 0.924 mm) and a small worker group (head width < 0.924 mm). The foraging worker population comprised two distinct groups – 25.64% were large workers and 74.36% were small workers. Larger workers delivered heavier seeds faster than smaller workers, but this difference became less apparent when lighter seeds were being carried. When large prey such as crickets was encountered during foraging, S. geminata partitioned their tasks into cutting and transportation. The large workers were observed to cut cricket prey into fragments with their longer mandibles, and the small workers then transported these fragments back to the nest. These results present evidence of task partitioning among tropical fire ants, with different tasks being performed by ants of different castes.