Changing dynamics of the pine beauty moth (Panolis flammea) in Britain: the loss of enemy free space?

Abstract

1 The pine beauty moth Panolis flammea has two main host plants in Britain: Pinus sylvestris (Scots pine), which is the ancestral food plant where the insect is never abundant enough to cause tree mortality, and Pinus contorta (lodgepole pine), an introduced host tree that has experienced periodic widespread tree mortality due to this pest. 2 We review the recent literature, published mostly after the year 2000, regarding the impact of natural enemies on the population dynamics of P. flammea in Britain. 3 The natural enemies of P. flammea are more diverse and abundant in Scots pine habitat than in lodgepole pine habitat and some of them show differential selection for P. flammea larvae in Scots pine habitat over those located in lodgepole pine habitat. 4 It is concluded that the difference in the population dynamics of this insect in the two different habitats was probably the result of the P. flammea finding enemyfree space in lodgepole pine habitat. 5 Recent evidence on the diversity and impact of natural enemies on lodgepole pine has demonstrated that they currently have a much more significant impact on this pest than they did in the 1970s and 1980s, when outbreaks were frequent.

Interpreting insect declines: seven challenges and a way forward

“…One logical precondition for estimating rates of long-term population decline is to have a sound quantitative estimate of historical population abundance. Frustratingly, such estimates are rarely available, as the vast majority of 'decline' studies only begin after numbers were perceived to be changing (Bonebrake et al, 2010); a similar picture is seen with pest insects, where studies are typically only started in response to outbreaks (Watt & Hicks, 2000;Hicks et al, 2008). At face value, this might suggest that current decline estimates should, on average, be underestimates of the longer-term trends (for instance, saproxylic insects, such as Rhysodes sulcatus Fabricius 1787, are thought to have been declining across Europe for the past 3000 years due to progressive loss of old-growth forests; Speight, 1989).…”

Plant genotype and the preference and performance of herbivores: cultivar affects apple resistance to the florivorous weevil Anthonomus pomorum

“…In most instances, the preference of adult females determines host plant infestation by their offspring (Gripenberg et al ., ). Female preference should be positively related to offspring performance unless female host selection is dominated by other factors, such as female avoidance of enemies or competitors (Hicks et al ., ; Plath et al ., ) or female incapability to reliably assess host quality (Murdoch et al ., ). If positive preference–performance relationships occur, they may be expressed in fastest development and highest final body size of offspring on the preferred, most suitable host plant.…”

Phylogeny, Systematics and Biogeography of the Genus Panolis (Lepidoptera: Noctuidae) Based on Morphological and Molecular Evidence

“…In this case there is a risk that it could become a pest on native pine species, but experience from P. flammea in Britain point to the possibility for control by generalist natural enemies after an initial period in an “enemy-free space” [61].…”

“…In conclusion, it can be noted that Panolis has no members in the New World today, but the history of the genus suggests a clear possibility for a representative of the Palearctic clade to become established as an invasive species in the Nearctic taiga, for instance following a human-aided accidental introduction. In this case there is a risk that it could become a pest on native pine species, but experience from P. flammea in Britain point to the possibility for control by generalist natural enemies after an initial period in an “enemy-free space” [61] .…”