Cell death and changes in primary metabolism: the onset of defence in Eucalyptus in the war against Leptocybe invasa.

BACKGROUND: Here, we investigated changes in primary metabolism and cell death around oviposition sites in two hybrid clones of Eucalyptus with different degrees of resistance to Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae), as well as tolerance to water deficiency. RESULTS: We showed that apices of the resistant clone with oviposition had a higher content of amino acids, organic acids and the compound putrescine compared with those of the susceptible clone with oviposition. By contrast, apices of the resistant clone with oviposition had lower sugar and pyruvate organic acid content than those of the susceptible clone with oviposition. Small areas of necrosis were induced around the oviposition sites in the stem apices of Eucalyptus 24 h after infestation. The resistant clone developed larger necrotic areas that showed progressive increases 24-72 h after infestation compared with the susceptible clone, in which cell death was significantly lower and no changes were observed in necrotic area over time. Thus, the programmed death of cells around the egg, modulated by several amino acids, is likely the first defence response of Eucalyptus against L. invasa. CONCLUSION: Our results serve as the basis for the early identification of key metabolites produced in plants in defence against galling insects. © 2022 Society of Chemical Industry.

Differential development times of galls induced by Leptocybe invasa (Hymenoptera: Eulophidae) reveal differences in susceptibility between two Eucalyptus clones.

BACKGROUND: The significance of morphological responses of hosts on susceptibility against gall-inducing insects is relatively unknown, especially in planted forests. Here, we investigate the temporal morphological responses (gall development) induced by the invasive gall wasp Leptocybe invasa and the subsequent insect development in two Eucalyptus clones. RESULTS: Our results identified a novel stage of gall development, not previously reported, termed here 'brownish ring'. In both hosts similar gall development stages were observed. Although L. invasa oviposited in both clones, comparison of external morphological traits of galls over time revealed a differential response in the number of galls between clones. Comparison of the developmental time of each gall and insect stage between clones suggests that plant defense mechanisms against L. invasa are activated shortly after oviposition by the wasp, yet before gall formation. CONCLUSION: Gall number is an important parameter that should be used to measure host susceptibility among Eucalyptus clones. To the best of our knowledge, this is the first study showing differential morphological responses induced by a galling insect, even before gall formation, revealing differences in susceptibility between different plant hosts. These findings provide insight into the use of early stages of gall formation by L. invasa to prevent invasion and establishment of this pest.

A new genus and species of Lasiopteridi (Diptera, Cecidomyiidae) associated with Myrciaria delicatula (Myrtaceae) from Brazil, with identification keys of tribes and unplaced genera

Fernandesia meridionalis Rodrigues & Maia, a new genus and species of Cecidomyiidae associated with Myrciaria delicatula O. Berg (Myrtaceae) is described and illustrated (male, female, pupa, and larva) based on material from Rio Grande do Sul, Brazil. The new genus belongs to Lasiopteridi, but it cannot be placed to tribe. A key to the tribes of Lasiopteridi and one to the unplaced genera of Neotropical Lasiopteridi are given.

Fernandesia meridionalis Rodrigues & Maia, um novo gênero e espécie de Cecidomyiidae associado à Myrciaria delicatula O. Berg (Myrtaceae) é descrito e ilustrado (macho, fêmea, pupa e larva) baseado em material do Rio Grande do Sul, Brasil. O novo gênero pertence a Lasiopteridi, mas não pode ser posicionado em tribo. Uma chave para as tribos de Lasiopteridi e uma chave para os gêneros neotropicais não posicionados de Lasiopteridi são dadas.

Coleopterous galls from the Neotropical region

Data on Neotropical coleopterous galls were compiled from the literature, which showed that 82 galls have so far been recorded among 77 plant species. The Fabaceae and Asteraceae plant families display the greatest richness in galls. Most galls are induced on stems or buds, while leaves constitute the second most attacked plant organ. Only 16 coleopteran gallers have been identified at the species level; most records are presented at the order level. The identified species belong to four families: Apionidae, Buprestidae, Curculionidae and Erirhinidae. The galls are found in Argentina, Brazil, Belize, Chile, Colombia (probably), Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama and Venezuela. Eighteen species of Coleoptera are inquilines of galls and are associated with 18 plant species, most frequently with Asteraceae, Melastomataceae and Fabaceae. The inquilines were recorded mainly in leaf galls induced by Cecidomyiidae (Diptera). The identity of these weevils is poorly known. General data indicate a lack of taxonomic studies in the Neotropical region.

Informações sobre galhas induzidas por Coleoptera na região neotropical foram compiladas a partir da literatura. Oitenta e duas galhas foram assinaladas em 77 espécies de plantas. Fabaceae e Asteraceae foram as famílias botânicas que apresentaram maior riqueza de galhas. A maioria das galhas desenvolveu-se em caule ou gema; as folhas foram o segundo órgão vegetal mais atacado. Apenas 16 indutores estão identificados em nível de espécie, estando a maior parte dos registros em nível de ordem. As espécies identificadas pertencem a quatro famílias: Apionidae, Buprestidae, Curculionidae e Erirhinidae. As galhas foram coletadas na Argentina, Brasil, Belize, Chile, Colômbia (provavelmente), Costa Rica, El Salvador, Guatemala, Honduras, México, Nicarágua, Panamá e Venezuela. Dezoito espécies de Coleoptera são inquilinas de galhas e estão associadas com 18 espécies de planta, sendo mais freqüentes em are Asteraceae, Melastomataceae e Fabaceae. Os inquilinos ocorreram principalmente em galhas foliares induzidas por Cecidomyiidae (Diptera). O conhecimento taxonômico desses besouros é escasso, indicando a carência de estudos na região neotropical.

Coleopterous galls from the Neotropical region

Data on Neotropical coleopterous galls were compiled from the literature, which showed that 82 galls have so far been recorded among 77 plant species. The Fabaceae and Asteraceae plant families display the greatest richness in galls. Most galls are induced on stems or buds, while leaves constitute the second most attacked plant organ. Only 16 coleopteran gallers have been identified at the species level; most records are presented at the order level. The identified species belong to four families: Apionidae, Buprestidae, Curculionidae and Erirhinidae. The galls are found in Argentina, Brazil, Belize, Chile, Colombia (probably), Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama and Venezuela. Eighteen species of Coleoptera are inquilines of galls and are associated with 18 plant species, most frequently with Asteraceae, Melastomataceae and Fabaceae. The inquilines were recorded mainly in leaf galls induced by Cecidomyiidae (Diptera). The identity of these weevils is poorly known. General data indicate a lack of taxonomic studies in the Neotropical region.

Informações sobre galhas induzidas por Coleoptera na região neotropical foram compiladas a partir da literatura. Oitenta e duas galhas foram assinaladas em 77 espécies de plantas. Fabaceae e Asteraceae foram as famílias botânicas que apresentaram maior riqueza de galhas. A maioria das galhas desenvolveu-se em caule ou gema; as folhas foram o segundo órgão vegetal mais atacado. Apenas 16 indutores estão identificados em nível de espécie, estando a maior parte dos registros em nível de ordem. As espécies identificadas pertencem a quatro famílias: Apionidae, Buprestidae, Curculionidae e Erirhinidae. As galhas foram coletadas na Argentina, Brasil, Belize, Chile, Colômbia (provavelmente), Costa Rica, El Salvador, Guatemala, Honduras, México, Nicarágua, Panamá e Venezuela. Dezoito espécies de Coleoptera são inquilinas de galhas e estão associadas com 18 espécies de planta, sendo mais freqüentes em are Asteraceae, Melastomataceae e Fabaceae. Os inquilinos ocorreram principalmente em galhas foliares induzidas por Cecidomyiidae (Diptera). O conhecimento taxonômico desses besouros é escasso, indicando a carência de estudos na região neotropical.