Does Temperature-Mediated Reproductive Success Drive the Direction of Species Displacement in Two Invasive Species of Leafminer Fly?

Abstract

Liriomyza sativae and L. trifolii (Diptera: Agromyzidae) are two highly invasive species of leafmining flies, which have become established as pests of horticultural crops throughout the world. In certain regions where both species have been introduced, L. sativae has displaced L. trifolii, whereas the opposite has occurred in other regions. These opposing outcomes suggest that neither species is an inherently superior competitor. The regions where these displacements have been observed (southern China, Japan and western USA) are climatically different. We determined whether temperature differentially affects the reproductive success of these species and therefore if climatic differences could affect the outcome of interspecific interactions where these species are sympatric. The results of life table parameters indicate that both species can develop successfully at all tested temperatures (20, 25, 31, 33°C). L. sativae had consistently higher fecundities at all temperatures, but L. trifolii developed to reproductive age faster. Age-stage specific survival rates were higher for L. sativae at low temperatures, but these were higher for L. trifolii at higher temperatures. We then compared the net reproductive rates (R 0) for both species in pure and mixed cultures maintained at the same four constant temperatures. Both species had significantly lower net reproductive rates in mixed species cultures compared with their respective pure species cultures, indicating that both species are subject to intense interspecific competition. Net reproductive rates were significantly greater for L. sativae than for L. trifolii in mixed species groups at the lower temperatures, whereas the opposite occurred at the higher temperature. Therefore, interactions between the species are temperature dependent and small differences could shift the competitive balance between the species. These temperature mediated effects may contribute to the current ongoing displacement of L. sativae by the more recent invader L. trifolii in warm climatic areas of China.

Influence of Temperature on Intra- and Interspecific Resource Utilization within a Community of Lepidopteran Maize Stemborers

“…The role of temperature in influencing varied competitive abilities of interacting species has been reported from three Drosophila species [ 61 ], between small and large seed beetle species Stator limbatus [ 34 ], the invasive fruit fly Bactrocera invadens Drew, Tsuruta & White over the indigenous fruit fly, Ceratitis cosyra (Walker) (Diptera: Tephritidae) [ 62 ] and two invasive leaf miner flies Liriomyza sativae Blanchard and L . trifolii (Burgess) (Diptera: Agromyzidae) [ 63 ]. In these studies, the competitive abilities of one of the competing species was enhanced by either low or high temperatures.…”

Niche comparison among two invasive leafminer species and their parasitoid Opius biroi: implications for competitive displacement

“…Moreover, a similar displacement process is proceeding in its area of invasion, such as in south Jiangsu, China 32 . Most papers published addressing the factors that mediate competitive displacement between L. trifolii and L. sativae have focused on the effects of environmental differences or human-mediated influences, including insecticides 15 , 17 , cropping systems 18 , temperature variations 33 and parasitoids 25 . Beyond these environmental factors, the inherent mechanisms of this displacement are still unclear.…”

DNA-based identifications reveal multiple introductions of the vegetable leafminer Liriomyza sativae (Diptera: Agromyzidae) into the Torres Strait Islands and Papua New Guinea

“…Therefore the species of Liriomyza that invades an area appears highly dependent on the movement of host plant material between areas by humans. If more than one polyphagous Liriomyza species is present within a region, species distributions appear to shift due to competition mediated through insecticide resistance (Gao et al , 2012) or differences in environmental tolerances (Huang & Kang, 2007; Tantowijoyo & Hoffmann, 2010; Wang et al , 2014).…”