Functional response of Cosmoclopius nigroannulatus (Hem.: Reduviidae) to different densities of Spartocera dentiventris (Hem.: Coreidae) nymphae

Abstract

This study evaluated the functional response of the predator Cosmoclopius nigroannulatus on first instar nymphae of Spartocera dentiventris, both species associated with Nicotina tabacum. The experiment was carried out in laboratory conditions: 27 +/- 1 degree C; 80 +/- 5%, RH; 12 h, photophase. Ten newly emerged adults of each sex of C. nigroannulatus were used in each of five densities (5, 15, 25, 35, and 45 individuals) of S. dentiventris nymphae. The predators were observed every 24 h for five days, when the number of dead and/or consumed nymphae was recorded. The results showed a positive correlation between the number of ingested nymphae and the increase in prey density. Females ingested more nymphae than the males. The estimated handling time per prey (Th) was higher in males (3.07 h) than in females (1.93 h), with total handling time (Th x Na) increased with density. Other components of the functional response, such as attack rate (a'), searching time (Ts), and search efficiency (E) showed, in neither males nor females, a negative correlation regarding density. The results indicated a higher predatory efficiency in the females. The components of the functional response fitted significantly the randomic model of the Holling discs equation (Na = N [1 - exp[- a'(T - ThNa)]]), evidencing a functional response of type II.

Non‐linear feeding functional responses in the Greater Flamingo (Phoenicopterus roseus) predict immediate negative impact of wetland degradation on this flagship species

“…According to the equations of types II and III models, intake rate is equal to zero at food density = 0. In contrast, type I functional response with nonzero intercept is occasionally found in the literature (da Rocha and Redaelli ; Durant et al. ).…”

“…According to the equations of types II and III models, intake rate is equal to zero at food density = 0. In contrast, type I functional response with nonzero intercept is occasionally found in the literature (da Rocha and Redaelli 2004;Durant et al 2009). Hence, for types I functional response we evaluated models where the intercept of intake rate was forced to zero or not when food density was equal to zero.…”

The interplay among prey preference, nutrient enrichment and stability in an omnivory system

“…The functional response type II is employed in this analysis based on the fact that several works assert that this kind of functional response is commonly observed in nature (Hassell, 1978;Faria et al, 2004a,b;Rocha and Redaelli, 2004).…”

Leaf-Footed Bugs (Coreidae)

“…Mark-release-recapture in tobacco fi elds (Jesus et al 2002 ) documented the population dynamics of the bug over the tobacco growing season, showing an aggregated pattern of distribution and predation by the reduviid Cosmoclopius nigroannulatus Stål on the second generation of nymphs Canto-Silva & Romanowski ( 2003 ). This assassin bug shows a type II functional response when feeding on fi rst instar S. dentiventris (da Rocha and Redaelli 2004 ). Reported parasitoids of both S. dentiventris and S. lativentris include the eurytomid wasp Neorileya ashmeadi Crawford and the platygastrid Gryon gallardoi (Brèthes) (Becker and Prato 1982 ;Santos et al 2001 ).…”