We all remember those teenage years, mum shouting from the doorway to get up and go to school, giving her tit bits of advice and usually finishing a sentence with ‘Don’t argue, I know what’s best for you!’ But what about insects, I’ve never read a study where they try to get their young out of bed early: so, do they know best?
If an insect could talk, would they say ‘thanks mum’? Probably not, more likely ‘who are you’ and have to go onto the Jeremy Kyle show to be told ‘You ARE the mother!’ So, what should a good reporter do? You guessed it, an interview. After hours of searching (okay, ten minutes – I couldn’t find my shoes), an aphid was found (a small pear shaped true bug with sucking mouthparts) 7 and she was not impressed with what I had to say!
After staring hard at her proboscis (wow, suddenly my nose seems very inadequate) we launched into it:
“Can you explain why you are a good mother?”
She huffed. “Honestly have you never read Craig and Ohgushi,2 well, it’s called the naïve adaptatonist hypothesis (something in the way she said naïve makes me think she was directing that right at me, seriously, I’m getting sass off a bug). She continued “It explains that mothers will pick the best site for oviposition (turns out this meant egg laying, I didn’t want to admit it at the time that she had a better vocabulary than me) and by having this plant preference the young laid on these sites have the best survival rates to adulthood.”3 She added breezily “There’s been loads of studies on it.”
“…I mean its easier when we eat the same food as our young, you eat until you want to lay and then just find a good place to do it, perfect. But some of my friends don’t stay here the full year round. They like to travel and have two host plants.3 My friend Mary spends the summer in a tree but each year she pops back to shrubs when she lays eggs to overwinter.”
I sit and think. So are they truly good parents, more importantly, are they better than us?
She continued – “There’s no swanky hospital for us insects, I have to make decisions, I mean, obviously one plant is going to be more nutritious, but what happens if there’s another plant that offers better protection from predators?!”1
“So what happens if you pick the wrong plant” I enquired, I mean how bad could it be?
“Slow growth mostly…”
“Well, that doesn’t sound so…”
“… OR death, from predators or we might not be able to feed from the right leaves.”
I’m feeling guilty; death seems a bit much for just laying your egg in the wrong place. But I’m a reporter and time to play my trump card.
“I’ve heard you just lay your eggs in places which are only beneficial to you.”6
“Where’d you hear that?” she replied.
I shrugged “It’s just a theory.”
“What about the theory that states we lay young elsewhere in order to increase their lifespan?”
Touché! I had to admit I had looked, there are lots of studies out there with conflicting evidence! Some argue larval survival is connected to the mother’s oviposition choice, 5 others have found a weak or no effect.3 How are you suppose to make sense of all this?
“Have you read the latest meta-analysis?”
“Analysis, it’s a study which analyses the significance all written studies to see an overall effect, it’s fantastic, explains what I’ve been saying all along, we pick a site that best helps our young.”4
“What about the experiments that don’t work then?” Surely she couldn’t have an answer for everything!
She sighed. “Maybe when it didn’t work it was the research that had problems such as bad weather (though you should already be used to that), wrong plants so you had to make the best of a bad situation, too few insects involved or maybe these lab experiments are not as representative of the wild as you seem to think.”8
Well didn’t this just take a complex turn, I thought I had it all figured out. I don’t think I could make all these right choices, some days I can’t even find two socks that match.
“Nothing’s ever that simple, much to learn you still have, young writer” (wait, did she just quote star wars at me?) and then she was gone.
Turns out I’ve learnt lots, mums like to huff; they like to be right and as it turns out, they usually are, (but don’t tell mine that). So next time your mother gives you some advice, maybe you should listen to her; after all, mother knows best!
By Christina Faulder
- Björkman, C., Larsson, S. and Bommarco, R. 1997. Oviposition preferences in pine sawflies: a trade-off between larval growth and defence against natural enemies. Oikos, 79 (1), pp.45–52.
- Craig, T.P. and Ohgushi, T. 2002. Preference and performance are correlated in the spittlebug Aphrophora pectoralis on four species of willow. Ecological Entomology, 27 (5), pp.529-540.
- Friberg, M. and Wiklund, C. 2009. Host plant preference and performance of the sibling species of butterflies Leptidea sinapis and Leptidea Reali: a test of the trade-off hypothesis for food specialisation. Oecologia, 159 (1), pp.127-137.
- Gripenberg, S., Mayhew, P.J., Parnell, M. and Roslin, T. 2010. A meta-analysis of preference–performance relationships in phytophagous insects. Ecology Letters, 13 (3), pp.383-393.
- Ishiwara, M. and Ohgushi, T. 2008. Enemy-free space? Host preference and larval performance of a willow leaf beetle. Population Ecology, 50 (1), pp.35-43.
- Jervis, M.A., Ellers, J. and Harvey, J.A. 2008. Resource acquisition, allocation, and utilization in parasitoid reproductive strategies. Annual Review of Entomology, 53, pp. 361-385.
- Kindlmann, P. and Dixon, A.F.G. 2010. Modelling population dynamics of aphids and their natural enemies. In: Kindlmann, P., Dixon, A.F.G and Michaud, J.P. In. Aphid biodiversity under environmental change: patterns and processes. London: Springer Science & Business Media. pp.1-20.
- Mayhew, P.J. 2001. Herbivore host choice and optimal bad motherhood. Trends in Ecology & Evolution, 16 (4), pp.165-167.