Plant bugs (Heteroptera: Miridae) associated with roadside habitats in Argentina and Paraguay: Host plant, temporal, and geographic range effects

Between November 1999 and September 2001, mirid nymphs (Hemiptera: Miridae) were collected on wild and cultivated plants in central and northern Argentina and southeastern Paraguay. In the laboratory, nymphs were reared until adult emergence. Four (Bryocorinae, Deraeocorinae, Mirinae, and Orthotylinae) of the eight mirid subfamilies were collected during the study. Twenty-two mirid species on 43 putative host plant species were collected in Argentina, and five species of mirids on eight plant species were collected in Paraguay. Eighty-five new mirid-plant associations were recorded (only 112 mirid-plant associations had been reported previously for Argentina). Most of the mirids were in the subfamily Mirinae, tribe Mirini, and most of the host plants belonged to Asteraceae. Almost all mirids were collected on plants with flower buds present. In addition to host plant records, the phenology and pattern of plant use for the most abundant mirids are reported. Mirid richness and abundance varied according to the host plant species; the highest diversity and richness of mirids occurred in the western region of Argentina (Salta, Jujuy, and Tucumán provinces). The most frequently collected mirid, Taylorilygus apicalis (Fieber) (≈87% of the 35,970 collected mirids), was usually collected on Asteraceae. This exotic species could have affected the native mirid fauna in the study area. More research on the possible interactions between T. apicalis and the native mirids of Argentina and Paraguay is needed. Our results suggest that T. apicalis exhibits regional polyphagy, i.e., uses numerous hosts throughout its geographic range.Facultad de Ciencias Naturales y Muse

Plant bugs (Heteroptera: Miridae) associated with roadside habitats in Argentina and Paraguay: Host plant, temporal, and geographic range effects

Between November 1999 and September 2001, mirid nymphs (Hemiptera: Miridae) were collected on wild and cultivated plants in central and northern Argentina and southeastern Paraguay. In the laboratory, nymphs were reared until adult emergence. Four (Bryocorinae, Deraeocorinae, Mirinae, and Orthotylinae) of the eight mirid subfamilies were collected during the study. Twenty-two mirid species on 43 putative host plant species were collected in Argentina, and five species of mirids on eight plant species were collected in Paraguay. Eighty-five new mirid-plant associations were recorded (only 112 mirid-plant associations had been reported previously for Argentina). Most of the mirids were in the subfamily Mirinae, tribe Mirini, and most of the host plants belonged to Asteraceae. Almost all mirids were collected on plants with flower buds present. In addition to host plant records, the phenology and pattern of plant use for the most abundant mirids are reported. Mirid richness and abundance varied according to the host plant species; the highest diversity and richness of mirids occurred in the western region of Argentina (Salta, Jujuy, and Tucumán provinces). The most frequently collected mirid, Taylorilygus apicalis (Fieber) (≈87% of the 35,970 collected mirids), was usually collected on Asteraceae. This exotic species could have affected the native mirid fauna in the study area. More research on the possible interactions between T. apicalis and the native mirids of Argentina and Paraguay is needed. Our results suggest that T. apicalis exhibits regional polyphagy, i.e., uses numerous hosts throughout its geographic range.Facultad de Ciencias Naturales y Muse

Plant bugs (Heteroptera: Miridae) associated with roadside habitats in Argentina and Paraguay: Host plant, temporal, and geographic range effects

Between November 1999 and September 2001, mirid nymphs (Hemiptera: Miridae) were collected on wild and cultivated plants in central and northern Argentina and southeastern Paraguay. In the laboratory, nymphs were reared until adult emergence. Four (Bryocorinae, Deraeocorinae, Mirinae, and Orthotylinae) of the eight mirid subfamilies were collected during the study. Twenty-two mirid species on 43 putative host plant species were collected in Argentina, and five species of mirids on eight plant species were collected in Paraguay. Eighty-five new mirid-plant associations were recorded (only 112 mirid-plant associations had been reported previously for Argentina). Most of the mirids were in the subfamily Mirinae, tribe Mirini, and most of the host plants belonged to Asteraceae. Almost all mirids were collected on plants with flower buds present. In addition to host plant records, the phenology and pattern of plant use for the most abundant mirids are reported. Mirid richness and abundance varied according to the host plant species; the highest diversity and richness of mirids occurred in the western region of Argentina (Salta, Jujuy, and Tucumán provinces). The most frequently collected mirid, Taylorilygus apicalis (Fieber) (≈87% of the 35,970 collected mirids), was usually collected on Asteraceae. This exotic species could have affected the native mirid fauna in the study area. More research on the possible interactions between T. apicalis and the native mirids of Argentina and Paraguay is needed. Our results suggest that T. apicalis exhibits regional polyphagy, i.e., uses numerous hosts throughout its geographic range.Facultad de Ciencias Naturales y Muse

The shield-backed bug, <i>Pachycoris stallii</i>: Description of immature stages, effect of maternal care on nymphs, and notes on life history

The life history of the shield-backed bug, Pachycoris stallii Uhler (Heteroptera: Scutelleridae), immatures was studied on its host plant, Croton californicus Muell.-Arg. (Euphorbiaceae), in Baja California Sur, Mexico. Immature stages are described and illustrated. Pachycoris stallii is bi- or multivoltine and occurs in xeric areas with sandy soil where it is rarely encountered away from C. californicus. Nymphs and adults feed on seeds within C. californicus fruit. Bugs oviposit on the underside of leaves, and females guard their eggs and first-instar nymphs from natural enemies. Embryonic orientation of prolarvae is nonrandom; each embryo is oriented with its venter directed toward the ground. This orientation may facilitate aggregation of first instars. The longitudinal axes of eggs are always oriented upward at about a 16° angle of deviation from a line perpendicular to the leaf surface. This is the first recorded observation of this phenomenon in Pentatomoidea. Experimental removal of females guarding first instars results in 100% loss of nymphs, and this is attributed to disruption of the aggregative behavior of nymphs. Maternal guarding appears to be a net benefit to P. stallii, despite possible costs to the brooding female.Facultad de Ciencias Naturales y Muse

Relatório de estágio em farmácia comunitária

Relatório de estágio realizado no âmbito do Mestrado Integrado em Ciências Farmacêuticas, apresentado à Faculdade de Farmácia da Universidade de Coimbr

Affect of food provisioning on survival and reproductive success of the olive fruit fly parasitoid, Psyttalia lounsburyi, in the field

International audienceConservation biological control offers approaches that can be integrated into classical biological control programs to enhance pest suppression. Food subsidies, such as nectar and honeydew, can increase a parasitoid's fecundity either by extension of the reproductive lifespan, increasing the rate of egg maturation, or both. The olive fruit fly, Bactrocera oleae, is a major pest of olives in California, where a classical biological control program is currently underway using an exotic parasitoid, Psyttalia lounsburyi. We conducted a field study where female-male pairs of P. lounsburyi wasps were caged with B. oleae-infested olives, and provisioned either with or without food. Our study showed that adult feeding is crucial to P. lounsburyi survival and fecundity under field-cage conditions. Food provision increased P. lounsburyi survival and several components of the wasp's reproductive success; nevertheless, parasitism rates and offspring production were relatively low. This was probably due, at least in part, to location of host larvae in enemy-free space 'beyond the reach' of the wasp's ovipositor. Sex ratio of offspring was male-biased, perhaps due to inbreeding in the laboratory colony from which P. lounsburyi was sourced. Female wasps carried ca. 25-35 eggs at their time of death, suggesting that they were time limited rather than egg limited. Integration of conservation biological control (e.g., food provisioning) and classical biological control (release of an exotic natural enemy) have promise to suppress olive fruit fly populations. Evaluation of the effect of food provisioning on P. lounsburyi reproductive success under open field conditions is warranted

Management of Pyrethoid-Resistant Whiteflies in Arizona Cotton: Selection, Cross-Resistance, and Dynamics

In 1995, silverleaf whitefly, Bemisia argentifolii Bellows and Perring, resistance to the widely -used mixture of Danitol® (fenpropathrin) + Orthene® (acephate) was shown to be severe and widespread in Central Arizona cotton. Thereafter, laboratory experiments were undertaken to identify the other major insecticides that were affected by this resistance. Whiteflies were collected in November of 1995 from Maricopa (highly resistant) and Yuma (relatively susceptible) County locations in Arizona. A composite colony was established by combining Yuma and Maricopa whiteflies in a 4:1 ratio. After six generations of adult selection of this population with Danitol + Orthene, appreciable shifts in the concentration responses for pyrethroid, organophosphate, and carbamate insecticides were observed, indicating heritable variation for resistance in the source populations. From this we obtained definitive proof that resistance to Danitol + Orthene confers cross-resistance to Asana® (esfenvalerate), Capture® (bifenthrin), Danitol, Decis® (deltamethrin), Decis + Orthene, and Karate® (lambda-cyhalothrin). Additionally, selection with Danitol + Orthene resulted in statistically significant reductions in susceptibility to Curacron® (profenofos), Lannate® (methomyl), Monitor® (methamidaphos), and Ovasyn® (amitraz). Studies were performed to assess tolerance of Maricopa (pyrethroid- resistant) and Yuma (pyrethroid-susceptible) populations to a diversity of conventional insecticides currently registered for use in Arizona cotton, with the intention of finding compounds that showed promise for overcoming pyrethroid resistance. Of the materials evaluated, Curacron, Lannate, Lorsban® (chlorpyrifos), Ovasyn, Supracide® (methidathion), and Vydate® (oxamyl) were most promising. To determine to what degree pyrethroid resistance in cotton influenced resistance in winter vegetables and melons, and vice versa, whitefly populations were collected from a succession of these crops in Western and Central Arizona regions. In most instances, the whiteflies in Western Arizona were significantly more susceptible to Danitol + Orthene than those in Central Arizona. Significant decreases were found in susceptibility to Danitol + Orthene during the 1996 season at three of the four locations in which multiple crops were monitored. This emphasizes that pyrethroid resistance levels can be increased in whitefly populations from any of the cotton, melons, or other winter vegetable crops evaluated. Therefore, management of pyrethroid resistance in Arizona cotton will require harmonizing resistance management efforts and specifically limiting pyrethroid use in the entire crop complex