Browsing by Author "Harris, M.O."

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Association between ovipositional preferences and offspring fitness in Hessian fly (Diptera: Cecidomyiidae)
(Sri Lanka Association for the Advancement of Science, 2013) Ganehiarachchi G.A.S.M.; Harris, M.O.
Fitness consequences of selecting young leaves for oviposition in the Hessian fly
(Entomological Society of America, Cincinnati, Ohio., 2003) Ganehiarachchi G.A.S.M.; Harris, M.O.
As well selecting particular genotypes for oviposition, female Hessian flies select particular sites within an individual host plant. The youngest leaves of the wheat plant typically receive the greatest numbers of eggs. We quantified the preference of the ovipositing female for the younger leaves and then studied the consequences of this preference for the feeding stages of the Hessian fly. The survival and growth of larva that eclosed from the egg on young versus old leaves was compared across different larval densities. Species 1: Diptera Cecidomyiidae Mayetiola destructor (Hessian fly)
Occurrence and Parasitism of Sitodiplosis mosellana (Diptera: Cecidomyiidae) in North Dakota
(Entomological Society of America, San Diego,California, 2007) Knodel, J.J.; Ganehiarachchi G.A.S.M.; Kirk, A.; Harris, M.O.
Oviposition behavior of orange wheat blossom midge on low – versus high ranked grass heads
(Entomological Society of America, Fort Lauderdale, Florida, 2005) Ganehiarachchi G.A.S.M.; Harris, M.O.
The wheat midge, Sitodiplosis mosellana (Géhan) (Diptera: Cecidomyiidae), is a serious pest of wheat in North America, Europe, and China. Adult females oviposit on the modified leaves of the seed head. Larvae hatch and migrate short distances, establishing a feeding site on a developing seed. Oviposition behavior was described on low-ranked versus high-ranked grass heads. The high-ranked type was ‘Roblin’ hard red spring wheat (Triticum aestivum), with the seed head at an early stage of development, i.e. pre-anthesis. The three low-ranked plant types were 1) post-anthesis ‘Roblin’, 2) pre-anthesis ‘Key 24’ hard red spring wheat, and 3) pre-anthesis ‘Robust’ barley (Hordeum vulgare). The three low-ranked types were chosen because they consistently receive fewer eggs in the field. Observations of 2-day old mated females were conducted from mid-June to mid-August, during the 1 to 1.5 hours before and after sunset. In initial observations, behaviors of groups of females (4 per cage) were quantified using scan sampling methods, with the following scored: 1) the location of each female, i.e. on the seed head or the walls of the cage, and 2) behavior on the seed head, i.e. examining, with the ovipositor extended and touching the modified leaves, or sitting or walking, with the ovipositor telescoped. In a second set of observations, focal animal sampling was used to quantify the behavior of individual females from landing to flight away from the seed head. Observations showed that oviposition decisions are clearly influenced by information gained by examining the modified leaves of the seed head. Species 1: Diptera Cecidomyiidae Sitodiplosis mosellana (orange wheat blossom midge)
Why Oviposit There? Fitness Consequences of a Gall Midge Choosing the Plant’s Youngest Leaf
(Environmental Entomology, 2013) Ganehiarachchi G.A.S.M.; Anderson, K.M.; Harmon, J.; Harris, M.O.
For animals that lay eggs, a longstanding question is, why do females choose particular oviposition sites? For insects that lay eggs on plants there are three hypotheses: maximizing suitable habitat for juveniles, maximizing female lifespan, and maximizing egg survival. We investigated the function of the oviposition-site choice behavior of a gall midge, the Hessian fly, Mayetiola destructor (Say). In spite of living less than a day and having hundreds of eggs, the ovipositing female is choosy about the placement of eggs. Choosiness makes sense. The tiny gall-making neonate larva has limited movement and strict requirements for colonization. We examined whether offspring benefit from the Hessian fly female's preference for the plant's youngest leaf. To do this we restricted the female's access to the first, second, or third leaf of a seedling (wheat Triticum aestivum L.) plant. Being placed on older leaves did not impact egg survival or larval survival during migration to attack sites at the base of the plant, but did have negative impacts on egg-to-adult survival (reduced by 48%) and reproductive potential (reduced by 30-45%). These negative impacts appear to come from larvae having to search harder to find the limited number of reactive plant cells that can be reprogrammed to form the gall nutritive tissue. We propose that the ability of larvae to find these reactive cells in spite of being placed on an older leaf is important because it creates leeway for female behavior to evolve in the face of other selection pressures, e.g., attack by egg parasitoids.