Cannibalism in the pea aphid,Acyrthosiphon pisum

Abstract

Previous observations of cannibalism have been made in the aphidAcyrthosiphon pisum (L.): this article seeks to quantify factors contributing to such behaviors. We observed and quantified the responses of a number of clones and life stages to varying levels of starvation, in the form of increasingly desiccated Vica faba L. plants (receiving 50, 25, or 10 mL every second day) or a complete absence of host plant. We found that, while the longest incidences of cannibalism are carried out by juveniles (F = 3.45, P = 0.019, df = 3) and targeted at adults, the starvation treatments had the most significant effect on the prevalence of cannibalism in mature A. pisum (F = 2.24, P = 0.025, df = 9). Furthermore, there was no difference between the prevalence or duration of cannibalistic activities within and between different clones (P ≥ 0.05 in all cases), though juveniles were more likely to target unrelated aphids (V = 6 112, P = 0.011), and spent more time feeding on aphids from the same culture (V = 6 062, P = 0.018).

Standing on the shoulders of giants: young aphids piggyback on adults when searching for a host plant

“…Rare laboratory observations of pea aphid nymphs climbing on adults have been attributed to “cannibalism” [ 35 , 36 ], since the nymphs were sometimes seen contacting the adults’ bodies with their proboscis. We did observe riding nymphs extending their proboscis and touching the adults’ bodies (probing), but those events were rare and always lasted less than 2 min.…”

Suboptimal macronutrient ratios promote cannibalism in a generalist herbivore (Trichoplusia ni)

“…For example, insect herbivores can independently self‐regulate macronutrient intake (Despland & Noseworthy, 2006; Raubenheimer, 1992; Raubenheimer & Simpson, 2003) and select for limiting macronutrients (Le Gall & Behmer, 2014) through post‐ingestive mechanisms. Self‐regulation may include adjusting both the identity and concentration of proteases (Bolter & Jongsma, 1995; Jongsma et al, 1995) to counteract the expression of protease inhibitors (Fan & Wu, 2005; Hilder et al, 1993; Jongsma & Bolter, 1997), which limit food quality (Cooper et al, 2014; Karban & Baldwin, 1997; Orrock et al, 2017; Vijendravarma et al, 2013; Zago‐Braga & Zucoloto, 2004) or by deploying detoxifying oxidases (Brattsten et al, 1977; Heidel‐Fischer & Vogel, 2015). However, poor food quality (Cooper et al, 2014; Karban & Baldwin, 1997; Orrock et al, 2017; Vijendravarma et al, 2013; Zago‐Braga & Zucoloto, 2004), and more specifically, extreme nutrient deficiencies (Lavoie & Oberhauser, 2004; Taylor, 1989) have been shown to encourage herbivorous insects to engage in behavioural plasticity by seeking alternative nutrient sources in the form of conspecifics via cannibalism (Cooper et al, 2014; Simpson et al, 2006; Xiao et al, 2010; Zago‐Braga & Zucoloto, 2004).…”

Post-reproductive parthenogenetic pea aphids (Acyrthosiphon pisum) are visually identifiable and disproportionately positioned distally to clonal colonies

“…Although in some cases these aggregations may contain more than one clonal lineage, relatedness within pea aphid colonies is generally high (Mondor & Messing, 2007). While aggregation can have benefits even in the absence of kin (Hamilton, 1971), a wide variety of behaviors benefiting clone mates in aggregations of pea aphids have been documented, including adaptive suicide (McAllister, Roitberg & Weldon, 1990), increased tolerance for cannibalistic feeding (Cooper, Desjonqueres & Leather, 2014), and scent-marking predators (Mondor & Roitberg, 2004). Aphids at the edges of colonies are at the highest risk of attack (Duff & Mondor, 2012; Obata, 1986), and when attacked will mark the attacker with alarm pheromone, effectively decreasing the risk for clone mates (Mondor & Roitberg, 2004).…”