Biocontrol for dog strangling vine (Vincetoxicum rossicum): Longevity and egg maturation of Hypena opulenta (Lepidoptera: Erebidae)

Vincetoxicum rossicum is an invasive species that has been negatively impacting forests in Ontario, and Quebec over the past 40 years. This non-native species from the Ukraine is a highly competitive species capable of choking out understory plants and trees in Canadian forests. In North America this species can create monocultures, therefore decreasing species biodiversity. Both chemical and mechanical control have been used in the past to manage V. rossicum, however, these methods of control are not practical forms of management, especially where the spread of V. rossicum is wide spread. For this reason, using a classical biological control agent is the most logical next step for management, as biological control is a long term and sustainable management tool. To find a suitable agent researches went back to the Ukraine to find herbivores for V. rossicum. Hypena opulenta, a moth that feeds on V. rossicum was found, and extensive testing has shown that this moth is host specific for this invasive species. Feeding caused by H. opulenta can lead to plant mortality of Vincetoxicum spp. Hence the need to explore the fitness of this moth to ensure its establishment in Canadian forests. Measurements of success and fitness for insects can be determined using longevity and fecundity, as these analyses are used to better understand reproduction. For starters this study found that adult females live for 14 days, while males live for 10 days at 23°C (room temperature) and 75% relative humidity. Females also tended to weight more than males, and pupal weight can is a predictive measure for longevity. Measurements of pupal width or length can also predict longevity. It is also possible to make approximations for adult longevity using measurements of length and width of empty pupal casings, therefore making it possible to use these measurements for field populations as an indicator for their fitness. Pupal weight cannot predict fecundity or egg size for H. opulenta, however, it was discovered that females develop their eggs over time and need a preoviposition period of 24 hours for their eggs to grow in both size and number. Therefore, releases can be timed as to when eggs will be fully developed