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GHOST MOTH! (HALLOWEEN SPECIAL) · Cereal Killers

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Music.
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Hi, and welcome to Serial Killers, the podcast all about the pest diseases,
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problems of cereal crops.
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And today we have a Halloween special.
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And today's subject is the ghost moth, or in the scientific language, Hepialis humuli.
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So it's called humuli because it was thought that it used to eat the roots of hop plants.
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And hop's scientific name is humulus lupulus
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probably the best scientific name to
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say humulus lupulus so linnaeus
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carl von lynn the swedish botanist and
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zoologist who came up with scientific names originally he
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was the first person to describe the ghost moth and
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so he he believed it was eating hop
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roots so he named it hepialis humuli even
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though it's subsequently defined that doesn't eat hop roots
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it's still got that name so scientific names don't change very
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often as i said there are beetles going around.
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The place that are named after adolf hitler and people
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haven't bothered to change their names because they very
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rarely get changed unless there's a a reason
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that that's definitely the wrong name to give it a good
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example is if it's previously been described by somebody else or
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it's not actually belonging to that plant family or
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that insect family so hepiarlis humuli
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is the ghost moth it's related to the swift moths
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is in the swift moth swift moth family and
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they are very interesting moths now.
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You won't have you may not have heard of the ghost moth
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but it unless you're a naturalist but
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it does eat cereal plants it does eat a lot of horticultural crops
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as well and it's a really interesting insect to
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look at because it's got its biology is is unlike a
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lot of the pests and diseases that we've talked about before okay so
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it's common name the ghost moth is named
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because it's white color of the adult
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males that are about four to five centimeters long and they
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have this weird dance that they fly
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about in at night when they're mating and they
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sort of like they sort of fly in
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a pendulum fashion to attract the
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females and they do that for a very specific reason we'll
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go on to the females are not
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ghost colored but they're sort of like a mustard color and they're five
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to seven centimeters long they're not the most disgusting looking
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moths in the world they're quite attractive if you're into moths a mustard one
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and a white moth so and they're much larger so they're five to seven centimeters
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long so in science we call that sexual dimorphism when one of the sexes is I
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was going to say genders then, didn't want to get into that.
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Minefield one of the sexes is much
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larger or smaller or different shaped or things like that so
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there's some some crabs have different shaped claws and
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things like that like that depending on the sex and ghost
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moths they they look completely different okay so
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being a moth it's related to moths
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and caterpillars so moths and butterflies are lepidoptera
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and so they they always have caterpillars that
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then form a pupa a chrysalis or
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a cocoon and then the
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adult the flying adult normally then pupates
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out and lays eggs and the ghost
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moth is no different it produces caterpillars however this
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is the key difference the one of the key differences
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is that the caterpillars of the ghost moth are white
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and with a like a reddish brown head and
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they live under the ground eating plant roots and so they're
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often referred to as maggots or larvae not
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caterpillars even though they strictly speaking are caterpillars so you
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might mistake them for a grub of a of some other type of pest and they they
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can get fairly deep down in the soil and the ghost moth caterpillar can eat
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a wide range of different plants so what we term polyphagus it's not it's not.
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Obligate for one species of crop or plant for
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it to eat so it can eat cereals it can
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eat lettuce it's a big problem in carrots and it's
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especially a problem in forestry it also eats weeds
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like nettles and the reason it's a problem in
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forestry and not in cereals is because it's it takes
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two years from the egg being laid
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for it to pupate and then turn into an adult
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so they spend two years underground and as
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they spend two years underground the damage gets significantly
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worse in that second year and towards the end because
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they're eating so much more and their population grows now
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in a arable field you're going
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to get cultivation of some sort in
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in after at least after a year and so that
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brings up the caterpillars and they
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can be ate by their significant pest
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predators like birds badgers foxes
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parasitic wasps will attack them moles will eat them and especially bats okay
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so come back to that as well so unlike the very hungry caterpillar in the kids
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book that eats a sausage a salami a piece of cherry pie two leaves and,
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By the end, you know, it gets very hungry and has to have a rest. It has a stomachache.
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This one is eating cereals, lettuce, carrots, pines, nettles.
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And then after two years, it's pupating.
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So it is a very hungry caterpillar if you allow it to be in your crop for two years.
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Now, I said the parasitic wasps, every insect has a parasitic wasp that will attack it.
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Even parasitic wasps have parasitic wasps that attack it.
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And even those parasitic wasps that have parasitic wasps that attack them have
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parasitic wasps that attack them. So they are the underappreciated biocontrol wasps.
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But the bats are the interesting one when it comes to the ghost moth.
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So on our Halloween theme, we'll continue that with bats.
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And the reason bats are important is because the ghost moth cannot hear.
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It is a deaf moth. And
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so normally a lot of moths have
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ultrasonic hearing to warn them
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of bat attacks and they can evade the bat however
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the the ghost moth is deaf so it's
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thought that the ghost moth and
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other moth so moths after the ghost moth evolved hearing to
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to evade bats
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that evolved after these moths so these these moths
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evolutionary predate bats so what
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do they do to prevent themselves being eaten by bats well that's
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something called lecking so lecking
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is this twilight flight of the
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male ghost moths in this pendulum fashion and they all the males congregate
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together and they compete for the females they release a pheromone to attract
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the females and you might read that this pheromone is described as goats like
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like almost like it smells of goats but.
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On the literature it's a bit confusing because some of
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the literature says they smell of the goat moth so do
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they smell of the goat moth or do they smell of goats it's a
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bit confusing that so this lacking occurs at twilight and
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the white shiny ghost moths make
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a quite an interesting display and then that attracts
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the females and especially these pheromones that attract them
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and then they mate and then the males just fall down
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and die after they've mated and then the females they
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go off and lay eggs and they can lay up to 600 well on
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average they lay 600 eggs in four
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days but that range can be anywhere from 200 to
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1600 eggs so that's a lot of eggs and that's
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all the resources for those eggs has come
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from the caterpillar feeding on the plant roots
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none of that resources comes from the moth
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feeding on nectar or pollen of flowers as
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other moths might do because the ghost moth completely lacks any mouth parts
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or feeding parts in its adult phase so it can't taste it can't eat it can't
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hear anything so it's a good job it can smell because that's that's maybe why
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lacking so important because it's one of the few senses that it can actually do.
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So and after those those females have laid their
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eggs they go and die as well so they
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don't stay in their adult phase for very long and then
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they those obviously those eggs lay into the hatch into
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the larvae which can be up to five centimeters long they can
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actually live for up to three years as well in some situations and they
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grow they have 12 what we call instars or
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12 malts as i say second year they
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do most damage not sure how that relates to direct drilling
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but there could be an issue with direct drilling and not bringing ghost
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moths to the service but i mean don't let
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ghost moths keep you awake at night because they're not a major pest
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so they they pupate in april to may
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and then they emerge june to july so
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there's a there's a fairly long pupation period
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where they lie dormant or something not dormant but they're they're
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metamorphosizing in their chrysalis there other halloween
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moth related issues not to
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be confused with the the ghost moth with the death's
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head hawk moth which you will have
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seen on the film silence
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the lambs that's the one that has a sometimes it
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looks like it has a skull on its thorax on its
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back and in silence the lambs
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the the serial killer put it into people's throats
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it's pretty grim it's not the nicest
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of moths in reality either because it invades beehives.
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And steals honey and pollen from.
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The beehives and it tricks them into thinking that it's one of the bees and.
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It's it's an african species that migrates to the uk so it does that that species
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even though it's in silence of the lands that's based in southern usa it actually
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does one of the species does occur in the uk.
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But luckily, the Death's Head hawk moth is not a serial killer.
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It's not a pest of arable crops. But the ghost moth is.
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You don't need to change your cultivation strategies or pest and disease control
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systems because basically everything you do in arable systems keeps their numbers to a good minimum.
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It's not a vulnerable or endangered species, so you don't need to worry about that.
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It's just something interesting. if you're out in the fields in
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the evening you may see a lecking of
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ghost moths and yeah take it
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send us a picture if you've got one probably quite difficult to
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get a good picture because it's at twilight but it'd be very interesting to
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know if you've encountered any mass congregations of
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ghost moths on your farm or around where you
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live just going back to lecking i forgot to
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say how that's linked to bat predation and it's
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thought that the ghost moth congregate in
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this big lex and do their display and attract the females
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in a short period of time at twilight so.
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They can get their mating over and done with sort out.
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Which ones they want to mate with really quickly before the
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bats can come and predate them and eat them all up
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and so congregating together is a strategy that
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lots of animals use to to reduce predation and then and
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then making it occurs so in such a short period of time
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it means that they can they don't need to dodge bats they
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just get away mate die and then go and the females
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go off and lay eggs thanks very much for listening i really
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appreciate it as a thank you for reaching the end
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of this spooky halloween edition i'm going
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to give you a treat for in the
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spirit of halloween if you use the
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discount code ghost in capital letters on
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the utreema website you'll get a fantastic 13
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percent discount for the next two weeks so
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very much on brand for the halloween a 13
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percent discount if you use the discount code ghost all
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one word all one word is one word all
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capital letters i mean g h o s t you can
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use that on everything apart from black grass spores which are
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have a set price but everything else all the other biostimulants fertilizers
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biopesticides please use that code and
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if you like the podcast give it a like subscribe hit the
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bell icon if you want to be notified of when we've got new episodes and hopefully
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we'll have a new episode soon and probably put a little treat at the end of
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every podcast now to thank everyone who's took the time to listen to probably
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10 to 30 minutes of my absolute drivel thank you very much.