Internecivus suvoltus (Aphidoidea)
Oct. 22nd, 2006 12:15 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
hazelkHappy Birthday![[livejournal.com profile]](https://www.dreamwidth.org/img/external/lj-userinfo.gif)
elisi!
You once said you might like to read this, I'm not sure it counts as a present but here goes anyway...
I’m clearly not unique in finding As You Were a frustrating episode. There are many reasons but, as a biologist, the one that used to annoy me the most was that Suvolte demon. It’s not often that we get to learn so much about the life history of an MOTW but, even more than usual for a Doug Petrie McGuffin, every new piece of information about the beastie seems to directly contradict the last. Or does it? Case for the prosecution:
1) Suvolte are extremely rare, nearly extinct
and yet…
2) They multiply like tribbles
3) They take apart whole villages leaving no survivors
nevertheless…
4) One turns up in a crowded square in Sunnydale and runs off without so much as injuring a small child
5) They come all the way to the hellmouth to spawn
so how come if…
6) They’re already breeding in nests all over South America?
Much to my horror, after careful consideration, all these facts turn out to be compatible, not only with each other, but with things real animals do. Suvolte demons could be as real as carnivorous tadpoles, marsupial mice and obscure species of aphid (but I still think they’d make crappy biological weapons).
Explainy:
High breeding rates and near extinction
High fertility, the ability to produce large numbers of offspring, is not the same as high fecundity, the ability to produce large numbers of surviving offspring. Human beings and most mammals have relatively low fertility but high fecundity, we take a long time to reach sexual maturity and produce small numbers of large long-lived offspring. By contrast, most insects, have high fertility but relatively low fecundity. They reach sexual maturity as soon as possibly and churn out vast numbers of small offspring the majority of whom do not survive. This life-style suits the harsh and unpredictable environments that these animals inhabit. A fruit fly may find itself in a situation where there’s no food around for days and then bingo someone throws out a pack of bananas. When that happens flies respond by making reproductive hay while the sun shines and breeding way faster than bunnies before everything gets eaten. After which the offspring disperse and most will die of starvation but a few might get lucky and bump into the next pack of bananas to come along. The combination Riley describes of near extinction with the ability to breed incredibly fast (as soon as conditions become favourable) is exactly what might be predicted.
Lame demon imagoes
The behaviour of the mature Suvolte that Buffy kills differs significantly from Riley’s description. However, it’s clear that alternate physical forms of these demons exist as the hatchlings had a very different morphology from the adult and it’s not a big intellectual leap to suppose that hatchlings and adults also have different behavioural tendencies. Non-demonic animal species, in which individuals show qualitative differences in morphology and/or behaviour under different conditions or stages of their life cycle are extremely common. For example tadpoles of the spadefoot toad are usually peaceful omnivores that feed on insects and algae. However, if the puddles they inhabit start to dry up carnivorus morphs develop with larger jaws and teeth, which attack and eat their puddle mates. The various stages of the Suvolte demon seem more like the larval/imaginal stages of holometabolous insects like bees and butterflies, the one adapted for feeding and other for mating/dispersal. This, however, raises the question of what function the lame runaway behaviour of the adult Suvolte is an adaptation for?
Possibly the key observation to consider here is that this particular individual has already spawned. Most warm blooded animals like ourselves are capable of reproducing repeatedly and continue to maintain good physical condition between spawns. There are, however, species of marsupial mice that like Pacific salmon and American eels go in for so-called big bang reproduction rather literally putting all their eggs in one basket. They reproduce once in a lifetime and immediately thereafter degenerate and die. Were they to survive they would simply be competition for their own offspring, which would not be in their long term evolutionary interests. If the Suvolte follow a similar strategy the Norwegian blue lameness of the adult could simply be an inevitable side-effect of its one long squawk.
Bees do it. Birds do it. But where do they do it?
It’s possible that when Riley said the Suvolte were breeders he simply omitted to add “once before they keel over and die (and by the way I got married).” Alternatively there’s a real distinction between breeding (in South American nests) and spawning (in the hellish equivalent of the wide Sargasso Sea). This is where the aphids come in.
In many species of aphid, eggs hatch in the spring to give rise to wingless females. These females settle on a host plant where they proceed to reproduce. Reproduction is asexual (and very prolific), colonies of thousands of identical females are produced over the summer months. In many species the colony is protected within a gall-like structure (which could correspond to the nests Riley mentioned). Come autumn, however, the change in the weather induces the production of winged male and female forms that reproduce sexually (this could be the spawning phase) and disperse or vice versa before laying their eggs. Most significantly (and this is the bit Spike failed to remember) it's the winter cold, which normally inhibits these eggs from hatching until spring.
elisi!You once said you might like to read this, I'm not sure it counts as a present but here goes anyway...
I’m clearly not unique in finding As You Were a frustrating episode. There are many reasons but, as a biologist, the one that used to annoy me the most was that Suvolte demon. It’s not often that we get to learn so much about the life history of an MOTW but, even more than usual for a Doug Petrie McGuffin, every new piece of information about the beastie seems to directly contradict the last. Or does it? Case for the prosecution:
1) Suvolte are extremely rare, nearly extinct
and yet…
2) They multiply like tribbles
3) They take apart whole villages leaving no survivors
nevertheless…
4) One turns up in a crowded square in Sunnydale and runs off without so much as injuring a small child
5) They come all the way to the hellmouth to spawn
so how come if…
6) They’re already breeding in nests all over South America?
Much to my horror, after careful consideration, all these facts turn out to be compatible, not only with each other, but with things real animals do. Suvolte demons could be as real as carnivorous tadpoles, marsupial mice and obscure species of aphid (but I still think they’d make crappy biological weapons).
Explainy:
High breeding rates and near extinction
High fertility, the ability to produce large numbers of offspring, is not the same as high fecundity, the ability to produce large numbers of surviving offspring. Human beings and most mammals have relatively low fertility but high fecundity, we take a long time to reach sexual maturity and produce small numbers of large long-lived offspring. By contrast, most insects, have high fertility but relatively low fecundity. They reach sexual maturity as soon as possibly and churn out vast numbers of small offspring the majority of whom do not survive. This life-style suits the harsh and unpredictable environments that these animals inhabit. A fruit fly may find itself in a situation where there’s no food around for days and then bingo someone throws out a pack of bananas. When that happens flies respond by making reproductive hay while the sun shines and breeding way faster than bunnies before everything gets eaten. After which the offspring disperse and most will die of starvation but a few might get lucky and bump into the next pack of bananas to come along. The combination Riley describes of near extinction with the ability to breed incredibly fast (as soon as conditions become favourable) is exactly what might be predicted.
Lame demon imagoes
The behaviour of the mature Suvolte that Buffy kills differs significantly from Riley’s description. However, it’s clear that alternate physical forms of these demons exist as the hatchlings had a very different morphology from the adult and it’s not a big intellectual leap to suppose that hatchlings and adults also have different behavioural tendencies. Non-demonic animal species, in which individuals show qualitative differences in morphology and/or behaviour under different conditions or stages of their life cycle are extremely common. For example tadpoles of the spadefoot toad are usually peaceful omnivores that feed on insects and algae. However, if the puddles they inhabit start to dry up carnivorus morphs develop with larger jaws and teeth, which attack and eat their puddle mates. The various stages of the Suvolte demon seem more like the larval/imaginal stages of holometabolous insects like bees and butterflies, the one adapted for feeding and other for mating/dispersal. This, however, raises the question of what function the lame runaway behaviour of the adult Suvolte is an adaptation for?
Possibly the key observation to consider here is that this particular individual has already spawned. Most warm blooded animals like ourselves are capable of reproducing repeatedly and continue to maintain good physical condition between spawns. There are, however, species of marsupial mice that like Pacific salmon and American eels go in for so-called big bang reproduction rather literally putting all their eggs in one basket. They reproduce once in a lifetime and immediately thereafter degenerate and die. Were they to survive they would simply be competition for their own offspring, which would not be in their long term evolutionary interests. If the Suvolte follow a similar strategy the Norwegian blue lameness of the adult could simply be an inevitable side-effect of its one long squawk.
Bees do it. Birds do it. But where do they do it?
It’s possible that when Riley said the Suvolte were breeders he simply omitted to add “once before they keel over and die (and by the way I got married).” Alternatively there’s a real distinction between breeding (in South American nests) and spawning (in the hellish equivalent of the wide Sargasso Sea). This is where the aphids come in.
In many species of aphid, eggs hatch in the spring to give rise to wingless females. These females settle on a host plant where they proceed to reproduce. Reproduction is asexual (and very prolific), colonies of thousands of identical females are produced over the summer months. In many species the colony is protected within a gall-like structure (which could correspond to the nests Riley mentioned). Come autumn, however, the change in the weather induces the production of winged male and female forms that reproduce sexually (this could be the spawning phase) and disperse or vice versa before laying their eggs. Most significantly (and this is the bit Spike failed to remember) it's the winter cold, which normally inhibits these eggs from hatching until spring.
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no subject
Date: 2006-10-22 06:12 pm (UTC)no subject
Date: 2006-10-22 09:51 pm (UTC)no subject
Date: 2006-10-22 07:26 pm (UTC)::boggles:: That's quite an adaptation!
If the Suvolte follow a similar strategy the Norwegian blue lameness of the adult could simply be an inevitable side-effect of its one long squawk.
I'm fairly sure that if my biology classes had had this much humor I would have probably retained more of them. Interesting stuff. It'd be great to go to a school with Buffy through the curriulum ;>
no subject
Date: 2006-10-22 10:00 pm (UTC)no subject
Date: 2006-10-22 11:01 pm (UTC)no subject
Date: 2006-10-23 08:35 am (UTC)no subject
Date: 2006-10-22 11:57 pm (UTC)Another possibility you could factor in might be that Suvolte demons live for a thousand years, and while they do produce dozens of offspring every time they mate, they only mate once every hundred years... ?
And perhaps the Suvolte in the episode ran off because guarding its eggs took priority over rampaging through downtown Sunnydale...but somehow, 'The Doctor' had stolen the eggs (in his TARDIS, presumably) and so the Suvolte was desparately running around looking for them again?
no subject
Date: 2006-10-23 08:49 am (UTC)The long lives of demons is quite a problem given that so much theory has been devoted to justifying our own much shorter ones. If ageing is due to investing more in reproduction than repair demons could just be inherently more durable, if it's because it's not worth aiming for immortality because one day you might be run over by a bus anyway, they (demons) may just have better traffic sense. I'll buy the egg guarding theory though. Neat.
no subject
Date: 2006-10-23 11:23 am (UTC)Thank you so much, it's a great present! *hugs*
no subject
Date: 2006-10-24 03:51 pm (UTC)I think Petrie probably got most of his ideas from memories of Alien and benefited from all the thought that went into that movie (the first one anyway).
no subject
Date: 2006-10-23 12:04 pm (UTC)Oh, and Sam Finn is definitely a robot. Or a semi-chipped vampire.
no subject
Date: 2006-10-24 03:54 pm (UTC)