Adriano Cavalleri

Predation of Gynaikothrips uzeli (Thysanoptera: Phlaeothripidae) By Androthrips ramachandrai (Thysanoptera: Phlaeothripidae)

ABSTRACT The galling thrips Gynaikothrips uzeli Zimmermann (Phlaeothripidae) has attained pest status by attacking the leaves of the weeping fig, Ficus benjamina. Another thrips species, Androthrips ramachandrai Karny (Phlaeothripidae), was recently reported feeding on G. uzeli immatures. Here we conducted choice tests with adults of A. ramachandrai to evaluate any preference for the immature stages of G. uzeli (egg, larva or pupa) in artificial arenas. Nochoice experiments were also conducted to measure the rate of feeding on each immature stage of the galling thrips by adults of A. ramachandrai in a period of 24 h. There was no significant preference by the predators for the different immature stages of G. uzeli, but adults consumed more eggs than larvae or pupae of the gall thrips. Here we discuss the predatory behavior of this thrips and its potential as a biological control agent against G. uzeli.

Flower stage and host plant preference by floral herbivore thrips (Insecta: Thysanoptera: Frankliniella) in a Brazilian savanna

This study shows that three Frankliniella (Thysanoptera) species have species-specific associations with their hosts: F. varipes–Faramea cyanea (Rubiaceae); F. musaeperda–Hancornia speciosa (Apocynaceae) and F. fulvipes–Solanum lycocarpum (Solanaceae). All thrips species had a marked preference for flowers in anthesis, as in this stage flowers provide food and protection from environment. Frankliniella musaeperda and F. varipes populations were female-biased while F. fulvipes was male-biased. Since many species of Frankliniella have economic importance, studies on the ecology of these species are essential, given the possibility of invasion of agricultural systems in the future.

Two new ectoparasitic species of Aulacothrips Hood, 1952 (Thysanoptera: Heterothripidae) associated with ant-tended treehoppers (Hemiptera)

Aulacothrips Hood, 1952 is a remarkable South American genus of ectoparasitic thrips which feed on gregarious ant-tended hemipterans (Hemiptera: Auchenorrhyncha). Here we describe two new species of this genus infesting membracid treehoppers in Colombia and Brazilian Amazon, and provide a key to the five Aulacothrips spp. now recognised. Aulacothrips levinotus n. sp. is unique in having pronotum with only two pairs of major setae; and Aulacothrips tenuis n. sp. has unusually long abdominal tergite IX. These findings will be helpful for understanding the species diversification in this genus, bringing a new perspective on the diversity of Aulacothrips spp. and their myrmecophilous hemipteran hosts.

A new leaf-galling Holopothrips (Thysanoptera: Phlaeothripidae) and the structural alterations on Myrcia retorta (Myrtaceae)

Holopothrips striatus sp. n. is described inducing leaf-galls on Myrcia retorta (Myrtaceae) in Southern Brazil. The thrips is one of the few species of Holopothrips known to have the metanotum with striate rather than reticulate sculpture. The galls are green with brownish spots, and are characterised by a mix of folding and rolling of the leaf lamina upwards.

Holopothrips molzi sp.n. (Thysanoptera, Phlaeothripidae): natural history and interactions in Myrtaceae galls

Holopothrips molzi sp. n. (Thysanoptera: Phlaeothripidae) is described from southern Brazil inducing leaf galls on Myrcia guianensis (Myrtaceae). Field observations revealed that the numbers of this thrips were highly variable within galls, and two other insect species were recorded living in these galls: Myrciathrips variabilis Cavalleri et al. (Phlaeothripidae) and an eulophid wasp (Hymenoptera). We investigated here if morphological traits of leaf and gall and abundance of the invader thrips were correlated with the gall inducers abundance. In order to determine the feeding habit and behaviour of M. variabilis and its interactions with the gall inducer we performed observations ad libitum and attack simulation tests on both thrips species to observe their response to possible invaders. Our results showed that leaf size is not related to H. molzi abundance, and gall size is relevant only when total numbers of both thrips species are considered. Myrciathrips variabilis was observed feeding on gall tissues, and no direct antagonistic interactions between the two thrips were recorded. The results of the behavioural tests simulating attacks were remarkably different in the two thrips species, indicating different strategies when threatened or disturbed. The interaction between the two thrips species is probably a case of inquilinism.

New Neotropical Haplothripini (Thysanoptera: Phlaeothripidae) with a key to Central and South American genera

ABSTRACT The tribe Haplothripini includes a large diversity of Thysanoptera–Phlaeothripinae, comprising more than 550 species in about 35 genera. They are characterised by having a maxillary bridge in the head, prosternal basantra well developed and fore wings with a median constriction. Members of this group are present in all geographical regions, but are particularly poorly studied in Central and South America. In this study, we describe a new genus and species, Myrciathrips variabilis gen. et. sp. nov., and a new Haplothrips species; and propose two new combinations: Karnyothrips grassoi (De Santis), and Mirothrips vespicola (De Santis). A key to the nine Haplothripini genera now recognised from Central and South America is provided, together with an updated key to Haplothrips and Mirothrips species. A total of 45 species of Haplothripini are now recognised from Central and South America, and a list of these and their distributions is given. The genera Karnyothrips, Haplothrips and Leptothrips are the most commonly encountered, and some exotic species such as Androthrips ramachandrai and Dolichothrips indicus are now widespread in the Americas.

The role of floral structure and biotic factors in determining the occurrence of florivorous thrips in a dystilous shrub

Elucidating the factors determining the occurrence of florivorous organisms is an essential step for comprehending arthropod–plant interactions, especially when considering florivores that use flowers/inflorescences as microhabitats. In this study, we characterize the interaction between florivorous thrips (Thysanoptera) and Palicourea rigida (Rubiaceae), a distylous hummingbird-pollinated shrub. We investigated the relative role of different factors in determining thrips occurrence in the flower and inflorescence microhabitats. Furthermore, we experimentally examined the protective role of corolla influencing thrips exploration of floral buds. Frankliniella musaeperda (Thripidae) was the only species recorded on P. rigida, feeding on floral tissue, pollen and nectar. Thrips occurrence was not related to distyly, but rather to floral stage. Open flowers presented the highest abundance of thrips, followed by senescent flowers and then buds. The experimental opening of buds translated in increased thrips occurrence, indicating that F. musaeperda manage to explore the microhabitat offered by the floral chamber, as long as there is an opening in the corolla. In inflorescences, thrips abundance was negatively related to the number of ants visiting extrafloral nectaries. We found that the marked difference between floral morphs of distylous plants is not necessarily reflected in the abundance of florivores. Thrips seek for floral cavities, preferentially those with fresh tissue, which may confer nutrient-rich food and protection. Buds also provide this; however, the enclosed petals are an effective barrier against F. musaeperda entrance. At inflorescence scale, presence of mutualistic ants in high numbers can drive away these flower-feeding insects. Despite the abundance of thrips in the flowers, there was no evidence of any functional relationship, either of pollination for flowers or of breeding for insects. We demonstrate here that in the flower/inflorescence microhabitat, structural and biotic factors play a key role in the exploitation and occupation by insect florivores.

Helionothrips errans (Thysanoptera: Thripidae): A New Threat to Native Orchids in Brazil

Helionothrips errans (Williams) (Thysanoptera: Thripidae) is reported for the first time in the Neotropics. This thrips breeds exclusively on Orchidaceae (Asparagales) leaves and has previously been found in Australia, USA, Europe, and southwestern Asia. We observed H. errans damaging the leaves of reintroduced Cattleya intermedia Graham ex Hook. plantlets, and attacked individuals showed reduction in the height of the aerial portion and in the average number of leaves per individual. Sumario Helionothrips errans (Williams) (Thysanoptera: Thripidae) e registrado pela primeira vez para os Neotropicos. A especie se alimenta exclusivamente em folhas de Orchidaceae (Asparagales) e ja foi encontrada para Australia, EUA, Europa e sudoeste asiatico. Nos observamos H. errans danificando folhas de plântulas reintroduzidas de Cattleya intermedia Graham ex Hook. e individuos atacados mostraram uma reducao na altura da porcao aerea e no numero de folhas por individuo. View this article in BioOne

Holopothrips diversity—a Neotropical genus of gall-inducing insects (Thysanoptera, Phlaeothripidae)

The genus Holopothrips represents the main Neotropical group of thrips associated with plant galls, and several of the 36 currently described species are known to induce or invade galls of other organisms. The existence of several Holopothrips specimens in collections that do not belong to any of the already described species, allied to the absence of basic biological information for several species, such as host plants and habit, shows that the current knowledge on the genus is severely lacking. Here we start addressing these problems, by describing 24 new species: H. acrioris, H. atlanticus, H. bicolor, H. brevicapitatum, H. cardosoi, H. curiosus, H. flavisetis, H. graziae, H. inconspicuus, H. infestans, H. irregularis, H. johanseni, H. kaminskii, H. longihamus, H. longisetus, H. magnus, H. maiae, H. nigrisetis, H. nigrum, H. punctatus, H. reticulatus, H. singularis, H. spermathecus, H. varicolor. This study also includes information on galls for several species; an updated and illustrated key to species; and comments on the morphological diversity of the group. With that, we hope to lay the taxonomic and morphological bases for future studies in this group, focusing on its diversity, ecology and phylogenetic relationships.

Prescribed patch burnings increase thrips species richness and body size in grassland communities

Prescribed patch burning is a well‐known tool for grassland and savanna management that has been recognised as a suitable strategy to enhance biodiversity at landscape‐level scales. Nevertheless, effective monitoring of the biota responses to fire is an essential step towards biodiversity conservation. We investigated fire effects on thrips communities (Thysanoptera) – a group of minute and diverse insect in grasslands. We performed a replicated small‐scale fire experiment in South Brazilian Campos, and tested for fire effects on total abundance, species richness of different feeding guilds (e.g. leaf, flower and fungal feeders) and thrips species body size in the short (1 month) and long‐term (1 year). We found positive fire effects on leaf herbivore richness in recently burned patches where the resprouted vegetation had enhanced nutritional quality, and also later on following the diversification of plant communities. The richness of fungivorous thrips was also benefited by resource heterogeneity in burned patches 1 year after fire. A positive fire effect on thrips community body size was also found at this time, possibly indicating that larger species had an advantage in dispersal to the spatially distributed burned patches across the unburned grassland matrix. Effects on total abundances were not detected. Our study emphasises the role of prescribed patch burnings in producing high quality resource‐rich habitat spots for Thysanoptera communities at local scales.