Dealing with host and food searching in a diurnal parasitoid: consequences of light at night at intra‐ and trans‐generational levels

Abstract

1. Light pollution is a widespread phenomenon with major consequences on nocturnal organisms from individual to community. However, its effects on diurnal organisms are still scarcely studied.2. We exposed diurnal parasitoid wasps (Venturia canescens) to low (0.7 lux) or high (20 lux) artificial light for two to eight consecutive nights, and quantified its consequences on their physiology and daytime behaviour compared to a control group (0 lux). We next considered potential trans-generational effects on offspring whose mothers were exposed to light pollution.3. While in the dark night the wasps showed no activity, exposure to artificial light triggered nocturnal activity and altered diurnal behaviours related to foraging. Wasps exposed to light at night had a greater propensity to choose hosts rather than food compared to controls. They also spent more time feeding when exposed to 0.7 lux of light at night. However, these behavioural modifications were not related to changes in individual energy reserves.4. Light pollution effects persisted at trans-generational level: offspring development time and latency before feeding increased when mothers were exposed to 0.7 lux light at night.5. Even at low intensity, light pollution alters foraging behaviour of a diurnal insect. Searching for hosts or food being essential for fitness, light pollution is likely to have long-term repercussions on insect populations.6. Light pollution caused behavioural modifications potentially beneficial for V. canescens in the short term. However, longer term studies (e.g. on lifetime reproductive success) are needed to fully understand its consequences on insects.

Street lighting has detrimental impacts on local insect populations

“…Indirect effects might also have added to the observed results. There could be increased top-down effects via niche expansion of diurnal predators, especially parasitoids ( 43 , 44 ). There might be bottom-up effects on host plant quality: HPS lighting negatively affects the development of Apamea sordens (a noctuid moth) by causing the food plant, grasses, to become physically tougher in lit areas ( 45 ).…”

Impacts of Artificial Light at Night on Nocturnal and Diurnal Insect Biology and Diversity

“…ALAN also affected a diurnal endoparasitoid Venturia canescens (Hymenoptera: Ichneumonidae) that parasitises the larvae of the Pyralidae, by extending its activity level into the night (Gomes et al, 2021); females of V. canascens exposed to low level ALAN also demonstrated a transgenerational effect with increased development time and increased latency for feeding in their offspring. In a massive collective phototactic response, 45 million individuals of Trimerotropis pallidipennis (Orthoptera: Acrididae), that are usually diurnal, were attracted to city lights in Las Vegas, USA (Tielens et al, 2021) during one of the perennial population outbreaks.…”

Световое Антропогенное Загрязнение: Действие На Насекомых

“…И наоборот, освещение может продлить пищедобывательную активность дневных и сумеречных насекомых [87]. Показано, что дневная оса-паразитоид Venturia canescens при освещении ночью с интенсивностью 0,7 и 20 люкс, что соответствует свечению неба вблизи городов и свету уличных фонарей, соответственно, удлиняет фуражирный период, что приводит к увеличению количества потомков у особей, содержавшихся в экспериментальных режимах, по сравнению с контролем (темнота ночью) [49,94]. Повышение освещенности в сумеречное время нарушает световую коммуникацию у светляков Photuris versicolor [41], уменьшая количество вспышек примерно на 70%.…”

“…светлого периода из-за светового загрязнения, такие как продление периода пищедобывательной активности, более раннее размножение, увеличение числа потомков в выводке и поколений за сезон [49,94]. Ночное освещение может «будить» дневных животных вследствие эффекта «маскинга» [83], в результате чего уменьшается время отдыха и его качество.…”