Héctor A. Cárcamo

Effects of Cannibalism and Intraguild Predation on Pondskaters (Gerridae)

Gerrid-gerrid predation can limit gerrid numbers and affect phenological patterns. In a field experiment with G. pingreensis, survival of small gerrids was dramatically reduced in the presence of larger juvenile instars, and survival of larger nymphs to the adult stage was significantly greater when given access to younger stages than when held by themselves. Mass of teneral female cannibals was significantly greater than that of females not given access to younger stages, but there was no effect on male mass or on development time of either sex. Predation by G. pingreensis on G. buenoi was not consistently more common than cannibalism in either laboratory or field experiments

Integrating the building blocks of agronomy and biocontrol into an IPM strategy for wheat stem sawfly

Integrating the building blocks of agronomy and biocontrol into an IPM strategy for wheat stem sawfly. Brian L. Beres , Héctor A. Cárcamo, David K. Weaver, Lloyd M. Dosdall, Maya L. Evenden, Bernard D. Hill, Ross H. McKenzie, Rong-Cai Yang, and Dean M. Spaner U. of Alberta, Edmonton, Alberta, AB Agriculture and Agri-Food Canada, Lethbridge, AB Montana State University, Bozeman, MT University of Alberta, Edmonton, AB Alberta Agriculture & Rural Development, Lethbridge, AB Corresponding authors E-Mail: brian.beres@agr.gc.ca

Kin discrimination and cannibalism in water striders (Heteroptera: Gerridae): another look

In a laboratory experiment, neither adults of Aquarius remigis or Limnoporus dissortis cannibalized non-kin first instars more frequently than their own progeny. However, males consumed significantly fewer first instar lymphs that did females. Results with A. remigis did not depend on adult hunger level or whether these adults were from lotic or lentic populations. Females of A. remigis did not prey preferentially of non-kin in choice experiments with third instar lymphs. Biological attributes of waterstriders suggest that kin discrimination should be rare in this taxon

Evaluation of Semiochemical-Baited Traps for Monitoring the Pea Leaf Weevil, Sitona lineatus (Coleoptera: Curculionidae) in Field Pea Crops

Abstract The pea leaf weevil (PLW), Sitona lineatus L., is a pest of field pea (Pisum sativum L.) and faba bean (Vicia faba L.) that recently invaded the Canadian Prairie Provinces. Although most damage is done by larvae that feed on root nodules, adults are easier to monitor than larvae. Both male and female weevils respond to a male-produced aggregation pheromone and to volatiles released by host plants. The current study tests the attractiveness of synthetic aggregation pheromone, 4-methyl-3,5-heptanedione, and host plant volatiles linalool, (Z)-3-hexenol, and (Z)-3-hexenyl acetate to PLWs in spring when weevils are reproductively active and in fall when weevils seek overwintering sites. Different combinations of semiochemical lures at various doses, released from a variety of devices were tested in pitfall traps. Semiochemical-baited traps captured both male and female weevils in both seasons but the sex ratio varied with season. Weevils did not respond in a dose-dependent manner to pheromone, as all pheromone lures were equally attractive. Pheromone release rate was determined by the release device and not the pheromone dose in the lure. The addition of plant volatiles sometimes increased weevil captures but plant volatiles alone were not attractive to PLW adults. An additional study tested the effect of trap type on weevil capture. Of the 12 different trap types tested, pheromone-baited pitfall traps were most successful in attracting and retaining weevils. Bycatch of other Sitona species was limited to a few specimens of the sweet clover weevil, Sitona cylindricollis Fahraeus.

Effect of Lygus spp and Botrytis spp on faba bean (Vicia faba L.) seed quality – are there insect-pathogen interactions?

Abstract: Lygus bugs and Botrytis fungal pathogen, the causal agent of chocolate spot in faba bean, can cause necrotic spots on faba bean seeds, thereby reducing market value. The mid-pod stage is the most susceptible stage for chocolate spot development and Lygus infestation in faba beans. Therefore, we hypothesised that the concomitant presence of Lygus spp. and Botrytis spp. might increase seed necrosis. Hence, the study was conducted to determine (i) the spatial and local distribution of chocolate spot and Lygus spp. in central and southern Alberta, and (ii) the association of chocolate spot disease severity and Lygus abundance. Chocolate spot and Lygus were present in all the counties surveyed. Chocolate spot had a negative association with Lygus abundance, but only the latter was significantly associated with seed necrosis. Botrytis spp. were frequently isolated from seeds despite the lack of expression of chocolate spot on the foliage. No significant effect of Lygus abundance on Botrytis isolation from seeds was found. Therefore, seed quality losses can occur both due to the fungal pathogen and the insect, which likely occupy different niches influenced by microclimate. Economic thresholds and management strategies will be required to keep insect populations and disease progression under check.