So why sexual cannibalism, is there an explanation for this bizzare behaviour?
Many questions arise when examining this, in our eyes, bizarre behaviour. When should and why do female mantids eat their potential partners? Do males allow themselves to be cannibalised?
Through looking at costs and benefits, in relation to the fitness regarding both sexes, of sexual cannibalism many hypotheses have been evaluated as possible answers (Johns & Maxwell 1997).
Through looking at costs and benefits, in relation to the fitness regarding both sexes, of sexual cannibalism many hypotheses have been evaluated as possible answers (Johns & Maxwell 1997).
Female Benefits
As aforementioned there is a common view that mantid females frequently cannibalise males when associated with sexual behaviour. Mating patterns are contributed to by females and it is consequently their actions that principally determine the pattern employed (Liske & Davis 1987).
One of the key drivers of reproduction is the females’ nutrition demands (Maxwell, Gallego & Barry 2010). The amount of prey available to a female has effects on her reproductive biology (Maxwell, Gallego & Barry 2010), with studies showing that with greater amounts of prey consumed females will lay larger oothecae (egg cases) containing higher numbers of eggs and thus producing more offspring (Lawrence 1992, Lelito & Brown 2006). Females gain valuable nutritional resources, and thus a benefit, through cannibalism of their male partner (Lelito & Brown 2006, Capinera 2008, Welke & Schneider 2012), within some species it has been shown to heighten the reproductive output (Maxwell, Gallego & Barry 2010). It is well documented that well-fed females show lower cannibalism rates and increased reproduction (Maxwell, Gallego & Barry 2010). Conversely a study did find that although females may gain nourishment, cannibalism of the male may interfere with the reception of sperm (Johns & Maxwell 1997).
Sexual cannibalism can be viewed as an extreme mechanism for mate choice (Prenter, MacNeil & Elwood 2006) or as an adaptive foraging strategy for females (Barry, Holwell & Herberstein 2008); with both ultimately benefiting the females’ survival and reproductive fitness. These hypotheses are particularly useful to explain pre-copulatory sexual cannibalism. When considering mate choice, preferred males will be allowed to mate whilst inferior males are cannibalised before copulation (Barry, Holwell& Herberstein 2008). Alternatively females can bias paternity through sexual cannibalism by manipulating copulation duration (Welke & Schneider 2012). The adaptive foraging hypothesis considers that females assess a male based on his value as a mate or his value as a meal (Barry, Holwell & Herberstein 2008). Nonetheless if a female consumes a male before mating she risks remaining unfertilised (Prokop & Radovan 2005).
However, clearly these mechanisms possess few benefits and even detrimental possibilities for male mantids (Barry, Holwell & Herberstein 2008).
One of the key drivers of reproduction is the females’ nutrition demands (Maxwell, Gallego & Barry 2010). The amount of prey available to a female has effects on her reproductive biology (Maxwell, Gallego & Barry 2010), with studies showing that with greater amounts of prey consumed females will lay larger oothecae (egg cases) containing higher numbers of eggs and thus producing more offspring (Lawrence 1992, Lelito & Brown 2006). Females gain valuable nutritional resources, and thus a benefit, through cannibalism of their male partner (Lelito & Brown 2006, Capinera 2008, Welke & Schneider 2012), within some species it has been shown to heighten the reproductive output (Maxwell, Gallego & Barry 2010). It is well documented that well-fed females show lower cannibalism rates and increased reproduction (Maxwell, Gallego & Barry 2010). Conversely a study did find that although females may gain nourishment, cannibalism of the male may interfere with the reception of sperm (Johns & Maxwell 1997).
Sexual cannibalism can be viewed as an extreme mechanism for mate choice (Prenter, MacNeil & Elwood 2006) or as an adaptive foraging strategy for females (Barry, Holwell & Herberstein 2008); with both ultimately benefiting the females’ survival and reproductive fitness. These hypotheses are particularly useful to explain pre-copulatory sexual cannibalism. When considering mate choice, preferred males will be allowed to mate whilst inferior males are cannibalised before copulation (Barry, Holwell& Herberstein 2008). Alternatively females can bias paternity through sexual cannibalism by manipulating copulation duration (Welke & Schneider 2012). The adaptive foraging hypothesis considers that females assess a male based on his value as a mate or his value as a meal (Barry, Holwell & Herberstein 2008). Nonetheless if a female consumes a male before mating she risks remaining unfertilised (Prokop & Radovan 2005).
However, clearly these mechanisms possess few benefits and even detrimental possibilities for male mantids (Barry, Holwell & Herberstein 2008).