Foraging behaviour of Helicoverpa armigera first instar larvae on crop plants of different developmental stages

Abstract

Understanding how insect pests forage on their food plants can help optimize management strategies. Helicoverpa armigera (Hu¨bner) (Lep., Noctuidae) is a major polyphagous pest of agricultural crops worldwide. The immature stages feed and forage on crops at all stages of plant development, damaging fruiting and non-fruiting structures, yet very little is known about the influence of host type or stage on the location and behaviour of larvae. Through semi-continuous observation, we evaluated the foraging (movement and feeding) behaviours of H. armigera first instar larvae as well as the proportion of time spent at key locations on mungbean [Vigna radiata (L.) Wilczek] and pigeon pea [Cajanus cajan (L.) Millspaugh] of differing developmental stages: seedling-and mature (flowering/pod fill)-stage plants. Both host type and age affected the behaviour of larvae. Larvae spent more time in the upper parts of mature plants than on seedlings and tended to stay at the top of mature plants if they moved there. This difference was greater in pigeon pea than in mungbean. The proportion of time allocated to feeding on different parts of a plant differed with host and age. More feeding occurred in the top of mature pigeon pea plants but did not differ between mature and seedling mungbean plants. The duration of key behaviours did not differ between plant ages in either crop type and was similar between hosts although resting bouts were substantially longer on mungbeans. Thus a polyphagous species such as H. armigera does not forage in equivalent ways on different hosts in the first instar stage.

Pulsed Odors from Maize or Spinach Elicit Orientation in European Corn Borer Neonate Larvae

“…In some species, mothers do not lay their eggs directly on the proper host (Harris et al 1999), while in others, larvae disperse actively, for example by ballooning (Zalucki et al 2002). Even in poorly mobile species, larvae that have adapted to a given host plant move within the plant to find adequate sources of food (Johnson and Zalucki 2005). They sometimes need to abandon their host and select another plant, for example when the plant resource is exhausted (Johnson and Zalucki 2005), when the competition from other herbivores becomes too strong (Pats and Ekbom 1992), when the plants' defense affects their health (Kester et al 2002), following infection by a disease (Evans and Allaway 1983), or because of predation pressure (Bernays 1997).…”

“…Even in poorly mobile species, larvae that have adapted to a given host plant move within the plant to find adequate sources of food (Johnson and Zalucki 2005). They sometimes need to abandon their host and select another plant, for example when the plant resource is exhausted (Johnson and Zalucki 2005), when the competition from other herbivores becomes too strong (Pats and Ekbom 1992), when the plants' defense affects their health (Kester et al 2002), following infection by a disease (Evans and Allaway 1983), or because of predation pressure (Bernays 1997). When they leave the host plant, their most relevant choice is to find a similar host to which they have adapted (Jermy et al 1967;de Boer 2004), sparing the need to readjust their metabolism to a new food source.…”

Controle de Helicoverpa armigera (Lepidoptera: Noctuidae) em soja com inseticidas químicos e biológicos

“…Poucos meses depois foi registrada no Paraguai (Senave..., 2013) e Argentina (Murúa et al, 2014). Cunningham & Zalucki (2014) As lagartas de H. armigera atacam tanto estruturas vegetativas quanto reprodutivas de seus hospedeiros, como cotilédones, folhas, flores e frutos (Johnson & Zalucki, 2005). Essa espécie apresenta ampla capacidade de dispersão (Farrow & Daly, 1987), pode migrar para uma distância de até 1.000 km (Pedgley, 1985), consegue sobreviver em condições adversas (Karim, 2000;Mironidis et al, 2010) e tem alto potencial reprodutivo (Naseri et al, 2009a(Naseri et al, , 2009b.…”

Feeding behavior of Heliconius erato phyllis (Fabricius) (Lepidoptera: Nymphalidae) larvae on passion vines

“…The definitions established as a result of these preliminary assessments followed the scheme proposed by Bernays et al (2004b) and Johnson and Zalucki (2005) The duration of meals (feeding bouts) was defined as a period of uninterrupted feeding of 3 min or more, separated by intervals of other behavioral acts (resting, walking, tasting, and vein cutting; Bernays et al 2004a;Shelomi et al 2010). Feeding with duration of 1 min or less was considered nibbles (Simpson 1981;Shelomi et al 2010) and was not included in analysis of temporal variation of meal time.…”