GLUTAMATE RECEPTOR-LIKE genes mediate leaf-to-leaf wound signalling.

Wounded leaves communicate their damage status to one another through a poorly understood process of long-distance signalling. This stimulates the distal production of jasmonates, potent regulators of defence responses. Using non-invasive electrodes we mapped surface potential changes in Arabidopsis thaliana after wounding leaf eight and found that membrane depolarizations correlated with jasmonate signalling domains in undamaged leaves. Furthermore, current injection elicited jasmonoyl-isoleucine accumulation, resulting in a transcriptome enriched in RNAs encoding key jasmonate signalling regulators. From among 34 screened membrane protein mutant lines, mutations in several clade 3 GLUTAMATE RECEPTOR-LIKE genes (GLRs 3.2, 3.3 and 3.6) attenuated wound-induced surface potential changes. Jasmonate-response gene expression in leaves distal to wounds was reduced in a glr3.3 glr3.6 double mutant. This work provides a genetic basis for investigating mechanisms of long-distance wound signalling in plants and indicates that plant genes related to those important for synaptic activity in animals function in organ-to-organ wound signalling.

Leaf consumption and duration of instars of the cassava defoliator Erinnyis ello (L., 1758) (Lepidoptera, Sphingidae)

The objectives of this research were to evaluate leaf consumption and the developmental time of the larvae of Erynnyis ello (L., 1758) (Lepidoptera, Sphingidae) reared on cassava, in order to obtain information for the integrated management of this pest. The larvae were reared on excised cassava leaves in Petri dishes and later in gerbox, and kept in chambers at 24 ± 2 ºC and 75 ± 10% RH. The total leaf area consumed by the larva to complete its development was 589.67 cm²; each of the five instars consumed, respectively: 1.89 cm²; 5.74 cm²; 17.48 cm²; 76.66 cm²; and 487.90 cm². The consumption by the first three instars was insignificant, and did not reach 5% altogether; the 4th represented 13%; the 5th presented a consumption significantly higher, about 82.7%. The total time for the larval development was 22.61 days, and the duration for each of the five larval instar was, respectively: 4.35; 3.19; 3.32; 4.52; and 4.94 days. The pre-pupal period lasted 2.29 days. Since the highest consumption is by the 5th instar larva, the control should be applied before this age to avoid heavier damages to the cassava crop.

Comparative description of the immature stages of two very similar leaf footed bugs, Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) (Hemiptera, Coreidae, Anisoscelini)

Holymenia clavigera (Herbst, 1784) and Anisoscelis foliacea marginella (Dallas, 1852) (Hemiptera, Coreidae) present a remarkable similarity regarding egg and nymphal morphology. On the contrary, their adult stages are remarkably different. This study describes and compares the immature stages of these two coreid species. Excepting for the last instar and the shape of the hind tibia from third to last instar, nymphs of both species were identical in their gross morphologies and ultrastructures. However, H. clavigera was significantly larger than A. foliacea marginella in all stages. Thus, we suggest that these species may have evolved through evolutionary convergence, parsimony between the immature stages after speciation, Müllerian mimicry or genetic drift.

Influence of Apion sp. (Brentidae, Apioninae) stem-galls on induced resistance and leaf area of Diospyros hispida (Ebenaceae)

We addressed the influence of the stem galls induced by an unidentified species of Apion sensu lato (Brentidae, Apioninae) on the host plant, Diospyros hispida (Ebenaceae) leaf area and induced resistance against a Cecidomyiidae (Diptera) leaf galls. The study was performed in a cerrado vegetation in Serra do Cipó, southeastern Brazil. Although the number of leaves produced on galled and ungalled shoots did not differ statically (p>0.05), the presence of the apionid galls influenced the area of the leaves on the attacked shoots of D. hispida. Leaves on galled stems were approximately 50% smaller compared to leaves in healthy stems. The average of the cecidomyiid leaf galls successfully induced on healthy shoots was higher compared to galls successfully induced on shoots galled by the apionid. The same pattern was found for the abundance of hypersensitive reactions against the cedidomyiid gall induction. Therefore, the ability of the cecidomyiid to successfully induce galls was not influenced by the apionid galler.

Adaptations of two specialist herbivores to movement on the hairy leaf surface of their host, Solanum guaraniticum Hassl (Solanaceae)

Plant trichomes can difficult the attachment and movement of small insects. Here, we examine the hypothesis that the success on the use of densely haired hosts by two cassidine species is determined by differential morphology and behavior. Larvae of Gratiana graminea (Klug, 1829) and Gratiana conformis (Boheman, 1854) move on the leaf surface of their host, Solanum guaraniticum Hassl by anchoring their tarsungulus on the trichome rays or by inserting the tarsungulus tip directly into epidermis. This kind of movement is only possible due to a similar tarsungulus shape among the species. Tarsungulus growth pattern is also similar between species, being relatively small on the posterior aperture, matching the diameter of the host plant trichome rays. The tarsungulus shape associated with differences on ontogenetic growth and attachment pattern allow these two Cassidinae larvae to efficiently move on the pubescent leaf surface of their host.

Insects associated with exposed decomposing bodies in the Colombian Andean Coffee Region

In Colombia, mainly classic forensic medicine methods were used to clarify crimes until 2004. However, other disciplines, including forensic entomology, started to be considered only after the New Accusatory System introduction in Bogotá and the Coffee Region in 2005. In order to provide tools for obtaining evidentiary material elements in judicial trials, it is presented here the succession of insects throughout the decomposition process of an exposed carcass of Sus scrofa Linnaeus 1758 (Suidae) and the Occurrence Matrix of colonizing species. This process was evaluated under ambient conditions in the Andean rural area of the city of Pereira, in the Mundo Nuevo district, located in a pre-montane Wet Forest area, from October to November 2006. A sampling period of 27 days and 3198 individuals were collected. We found these colonizing species in the following stages of decomposition: Lucilia eximia (Wiedemann, 1819) fresh; Hemilucilia semidiaphana (Rondani, 1850), Oxelytrum discicolle (Brullé, 1840), and Cochliomyia macellaria (Fabricius 1775) bloated; Chrysomya albiceps (Wiedemann 1819), Compsomyiops verena (Walker, 1849), Ophyra aenescens (Wiedemann, 1830) and Musca domestica Linnaeus, 1758 active; Fannia sp. advanced and Stearibia nigriceps (Meigen, 1826) remains. This study provides support tools to define the Post Mortem Interval that may be used by experts from government institutions and laboratories officially accredited.

Evaluating leaf litter beetle data sampled by Winkler extraction from Atlantic forest sites in southern Brazil

Evaluating leaf litter beetle data sampled by Winkler extraction from Atlantic forest sites in southern Brazil. To evaluate the reliability of data obtained by Winkler extraction in Atlantic forest sites in southern Brazil, we studied litter beetle assemblages in secondary forests (5 to 55 years after abandonment) and old-growth forests at two seasonally different points in time. For all regeneration stages, species density and abundance were lower in April compared to August; but, assemblage composition of the corresponding forest stages was similar in both months. We suggest that sampling of small litter inhabiting beetles at different points in time using the Winkler technique reveals identical ecological patterns, which are more likely to be influenced by sample incompleteness than by differences in their assemblage composition. A strong relationship between litter quantity and beetle occurrences indicates the importance of this variable for the temporal species density pattern. Additionally, the sampled beetle material was compared with beetle data obtained with pitfall traps in one old-growth forest. Over 60% of the focal species captured with pitfall traps were also sampled by Winkler extraction in different forest stages. Few beetles with a body size too large to be sampled by Winkler extraction were only sampled with pitfall traps. This indicates that the local litter beetle fauna is dominated by small species. Hence, being aware of the exclusion of large beetles and beetle species occurring during the wet season, the Winkler method reveals a reliable picture of the local leaf litter beetle community.

Leaf-litter amount as a factor in the structure of a ponerine ants community (Hymenoptera, Formicidae, Ponerinae) in an eastern Amazonian rainforest, Brazil

Leaf-litter amount as a factor in the structure of a ponerine ants community (Hymenoptera, Formicidae, Ponerinae) in an eastern Amazonian rainforest, Brazil. Leaf-litter may be an important factor in structuring ponerine ant communities (Hymenoptera, Formicidae, Ponerinae) in tropical rainforests. We specifically examined how leaf-litter affects the structure of a ponerine ant community in primary Amazonian rainforest sites at the Ferreira Penna Scientific Station, Pará, Brazil. A total of 53 species belonging to eight genera of three ponerine tribes were collected with mini-Winkler extractors. The amount of leaf-litter positively affected the abundance and richness of the ponerine ant community, and also influenced species composition. Nearby samples often had low species similarity, especially when adjacent samples differed in the amount of leaf-litter. Leaf-litter availability in Amazonian primary forests is a key factor for distribution of ground-dwelling ponerine species, even at small scales.

Influence of age and diet on the performance of Cephalonomia stephanoderis (Hymenoptera, Bethylidae) a parasitoid of the coffee berry borer, Hypothenemus hampei (Coleoptera, Curculionidae)

The importance of age and feeding on the performance of Cephalonomia stephanoderis (Hymenoptera, Bethylidae), a parasitoid of the coffee berry borer, Hypothenemus hampei (Coleoptera, Curculionidae) was investigated in the laboratory. Groups of female parasitoids were subject to the following treatments: a group fed during one, five and ten days after emergence of adults with coffee borer larvae; another group fed only with honey solution during five days after emergence; and as a control, a third group was kept without food for five days. At the end of each treatment, survivorship, parasitoid activity (walking and flying capacity in an arena), search capacity for finding coffee borer-infested berries, host feeding and oviposition (on immature hosts), were assessed. Unfed females showed a significant decrease in survivorship compared to individuals that were fed. The type of meal (insects or honey) did not significantly influence parasitoid activity, search and oviposition capacities. Females fed with honey solution significantly consumed less immature coffee borers. Younger females (one day old) walked and flew out of the arena significantly faster than older ones (5 and 10 days old). Implications of these results are discussed on the performance of C. stephanoderis as a biological control agent of the coffee berry borer.

The genome of the leaf-cutting ant Acromyrmex echinatior suggests key adaptations to advanced social life and fungus farming.

We present a high-quality (>100× depth) Illumina genome sequence of the leaf-cutting ant Acromyrmex echinatior, a model species for symbiosis and reproductive conflict studies. We compare this genome with three previously sequenced genomes of ants from different subfamilies and focus our analyses on aspects of the genome likely to be associated with known evolutionary changes. The first is the specialized fungal diet of A. echinatior, where we find gene loss in the ant's arginine synthesis pathway, loss of detoxification genes, and expansion of a group of peptidase proteins. One of these is a unique ant-derived contribution to the fecal fluid, which otherwise consists of "garden manuring" fungal enzymes that are unaffected by ant digestion. The second is multiple mating of queens and ejaculate competition, which may be associated with a greatly expanded nardilysin-like peptidase gene family. The third is sex determination, where we could identify only a single homolog of the feminizer gene. As other ants and the honeybee have duplications of this gene, we hypothesize that this may partly explain the frequent production of diploid male larvae in A. echinatior. The fourth is the evolution of eusociality, where we find a highly conserved ant-specific profile of neuropeptide genes that may be related to caste determination. These first analyses of the A. echinatior genome indicate that considerable genetic changes are likely to have accompanied the transition from hunter-gathering to agricultural food production 50 million years ago, and the transition from single to multiple queen mating 10 million years ago.

Emigration of a colony of the leaf-cutting ant Acromyrmex heyeri Forel (Hymenoptera, Formicidae)

Emigration of a colony of the leaf-cutting ant Acromyrmex heyeri Forel (Hymenoptera, Formicidae). Colony migration is a poorly studied phenomenon in leaf-cutting ants. Here we report on the emigration of a colony of the leaf-cutting ant A. heyeri in Brazil. The colony emigrated to a new location 47.4 m away from the original nest site, possibly because it had undergone considerable stress due to competitive interactions with a colony of Acromyrmex crassispinus.

A new genus and species of leaf miner (Lepidoptera, Gracillariidae) for Chile associated to the native tree Lithraea caustica

A new genus and species of leaf miner (Lepidoptera, Gracillariidae) for Chile associated to the native tree Lithraea caustica. We propose the new genus and species of Gracillariidae (Lepidoptera) Hualpenia lithraeophaga Mundaca, Parra &Vargas gen. nov., sp. nov., leaf miner of Lithraea caustica (Mol.) H. et Arn (Anacardiaceae) occurring in southern central Chile. Aspects of the life cycle, adult and larval morphology, development and feeding habits of the new genus and species are also presented. We emphasise the uniqueness and importance of this new species for broadening the current knowledge on the Chilean fauna of Gracillariidae.

Energy substrate used by workers of leaf-cutting ants during nest excavation

Energy substrate used by workers of leaf-cutting ants during nest excavation. In this study we aimed to ascertain whether leaf-cutting ant workers lose body reserves (fat or sugars) as a function of nest excavation. For each treatment, we isolated 10 workers of Atta sexdens into two experimental groups, Control (C- without excavation) and Soil (S- with excavation), which were kept for different time intervals (0, 24, 48 or 72 hours), totaling 700 tested workers. We then determined the concentration of soluble carbohydrates and total lipid content in them. The total carbohydrates were determined colorimetrically, based on the reaction between carbohydrates and sulfuric acid-phenol. For determination of lipids, the insects were immersed in organic solvent until they reached a constant weight. Our results showed that carbohydrates are consumed during nest excavation activities. In the experimental groups S24, S48 and S72, there was an average reduction of 5.82 (20.42%), 14.31 (44.96%) and 13.27 (43.96%) µ.mg-1 in soluble sugar when compared with the experimental groups that did not excavate. Furthermore, the lipids were not used during this activity. With respect to dry mass of the workers, their values were C0 = 8%, C24 = 10.4%, C48 = 9.2%, C72 = 10%, S24 = 9.2%, S48 = 8.7% and S72 = 8.5%. Our results show experimentally that the source of energy for nest excavation is carbohydrates, whereas lipids are conserved for other activities.

Energetic cost of digging behavior in workers of the leaf-cutting ant Atta sexdens (Fabricius)

Energetic cost of digging behavior in workers of the leaf-cutting ant Atta sexdens (Fabricius). During nest excavation, leaf-cutting ant workers undergo reduction in their body reserve, particularly carbohydrates. In order to estimate the energetic cost of digging, groups of 30 workers of the leaf-cutting ant Atta sexdens were sealed in a hermetic chamber for 24, 48 and 72 hours, with and without soil for digging, and had the CO2 concentration measured using respirometric chambers as well as volume of soil excavated (g). As expected, the worker groups that carried out soil excavation expelled more carbon dioxide than the groups that did not excavate. Therefore, a worker with body mass of 9.65 ± 1.50 mg dug in average 0.85 ± 0.27 g of soil for 24 hours, consuming ca. 0.58 ± 0.23 J. In this study, we calculate that the energetic cost of excavation per worker per day in the experimental set-up was ca. 0.58 J.

Egg laying site selection by a host plant specialist leaf miner moth at two intra-plant levels in the northern Chilean Atacama Desert

Egg laying site selection by a host plant specialist leaf miner moth at two intra-plant levels in the northern Chilean Atacama Desert. The spatial distribution of the immature stages of the leaf miner Angelabella tecomae Vargas & Parra, 2005 was determined at two intra-plant levels (shoot and leaflet) on the shrub Tecoma fulva fulva (Cav.) D. Don (Bignoniaceae) in the Azapa valley, northern Chilean Atacama Desert. An aggregated spatial pattern was detected for all the immature stages along the shoot, with an age dependent relative position: eggs and first instar larvae were clumped at apex; second, third and fourth instar larvae were mostly found at intermediate positions; meanwhile the spinning larva and pupa were clumped at basis. This pattern suggests that the females select new, actively growing leaflets for egg laying. At the leaflet level, the immature stages were found more frequently at underside. Furthermore, survivorship was higher for larvae from underside mines. All these results highlight the importance of an accurate selection of egg laying site in the life history of this highly specialized leaf miner. By contrast, eventual wrong choices in the egg laying site selection may be associated with diminished larval survivorship. The importance of the continuous availability of new plant tissue in this highly human modified arid environment is discussed in relation with the observed patterns.