Biologia de Neotrioza tavaresi Crawford, 1925 (Hemiptera, Psyllidae), galhador da folha do araçazeiro (Psidium cattleianum)

Abstract

ABSTRACT. Biology of the leaf gall inducer Neotrioza tavaresi Crawford, 1925 (Hemiptera, Psyllidae) on strawberry guava tree (Psidium cattleianum). A field study was conducted in Curitiba region, State of Paraná, southern Brazil, to describe the life cycle of Neotrioza tavaresi Crawford, 1925, a leaf galling insect in strawberry guava trees (Psidium cattleianum). Three cycles were observed (1997, 1998, 1999) during regular field trips and the insects were observed in Piraquara municipality, where 15 samples with 50 infested leaves were sampled in the 1997-98 cycle. Galls were dissected for detailed studies. Neotrioza tavaresi has a univoltine cycle in which adult individuals were found inside the galls from August onwards. The sexually mature insects with sex ratio 1, emerged from the galls after their dehiscence caused by feeding of the adult insects on the gall walls. Adult emergence started in early October and ended by early December, with its peak in November. Copulation took place as soon as adults exit the gall and egg laying started the next day. Females had more than 100 ovarioles containing 218.7±44.7 (n=50) fully formed eggs. This indicated the short sexual adult life-span (aprox. 5-7 days) of the species, also characterized by a concentrated oviposition. Adult individuals fed and laid their eggs on younger shoots of the plant. The bottoms of the yellowish eggs were inserted into the leaf tissue, mainly on its adaxial edge (78.1%). The nymphs hatched and, as they fed on the adaxial side of expanding leaves, modified the cell growth pattern and the roundshape galls developed on the adaxial side with one insect inside. The gall wall showed distinct layers, with the inner one suppliyng the food to the insects, and the outer layer supplying gall protection. Nymphs went through five instars and the exuviae remained stuck on a ball of wax inside the gall. All parasitoids found were Hymenoptera belonging to Chalcidoidea: Eulophidae (1 sp), Pteromalidae (2 spp) and Encyrtidae (3 spp). The findings suggest that leaf gall inducer and parasitoids insects and plant life cycles are closely connected and both leaf sprouting and gall opening seem to be triggered by the same environmental and plant conditions. The high abundance of shoots may favor insect performance as adult individuals can easily find an ideal place for feeding, copulating and laying eggs.

Contrasting effects of habitat management on different feeding guilds of herbivorous insects in cacao agroforestry systems

“…This family has species described as forest "pests" for several crops, especially Eucalyptus monocultures (Halbert & Manjunath, 2004;Silva et al, 2010), mainly because of the biological characteristics of the species. Adult psyllids are typically jumpers that only fly short distances, a condition that demonstrates their low dispersal ability (Butignol & Pedrosa-Macedo, 2003). Moreover, psyllids exhibit high reproductive rates, and females lay dozens of aggregate eggs in each reproductive event (Butignol & Pedrosa-Macedo, 2003;Halbert & Manjunath, 2004).…”

“…Adult psyllids are typically jumpers that only fly short distances, a condition that demonstrates their low dispersal ability (Butignol & Pedrosa-Macedo, 2003). Moreover, psyllids exhibit high reproductive rates, and females lay dozens of aggregate eggs in each reproductive event (Butignol & Pedrosa-Macedo, 2003;Halbert & Manjunath, 2004). The high reproductive rate facilitates rapid adaptation to a new host and leads to physical damage to the crop leaves, such as curled and deformed leaf blades, by aggregate populations.…”

Insect galls from Serra dos Pireneus, GO, Brazil

“…Usually, galling insects are associated with the conducting tissues drawing water and nutrients, causing deficiencies to the plant, compromising their development and reproduction (Butignol & Pedrosa-Macedo 2003). In some crops, some gall-midges (Cecidomyiidae: Diptera) can cause economic damage, as Jatrophobia brasiliensis (Rubsaamen, 1907) that forms galls on the upper surface of leaves of cassava, deforming them and hindering the normal development of the plant and Contarinia sorghicola (Coquillett, 1898) whose larvae feed on the floral ovary preventing the development of grain sorghum, and the considerable damage, where the panicles are fine and there are no grains formed (Nakano et al 1981).…”

Could the Extended Phenotype Extend to the Cellular and Subcellular Levels in Insect-Induced Galls?

“…cattleianum and P . myrtoides are both globoid [ 3 ], protrude to the abaxial surface of the leaf lamina, and have univoltine cycles [ 18 , 19 ]. To the extent of ecological and macro-morphological aspects, the phenotypic expression of the genes from the two species of Nothotrioza exerts biochemical influence on the cells of two species of Psidium .…”