Cicadas and Summer Bugs with Entomologist PJ Liesch

Robin is joined by UW-Madison entomologist PJ Liesch to talk about cicadas, spongy moths, Japanese beetles, Asian ladybeetles, and the scorpion.

Episode Transcript

(00:00):
Good morning. I'm Robin Colbert andthis is Madison Forum. I guess this
morning he's kind of the man ofthe hour these days. Youw Madison entomologist
PJ Leash, PJ? Can Icall you PJ? Thanks so much for
joining me. Yeah, great tobe here, and feel free to call
me PJ. All right, Sowhy are you so popular this year?

(00:20):
Is it all because of the cicadasor what? The akedas are definitely a
big factor, and when you thinkabout it, I mean, we have
just been getting pummeled with news articlesabout these periodicals Aketa's even going back into
the winter months January and February,it really started getting busy. And this

(00:41):
year has been special on that wehave had not one, but two groups
or broods of these periodicals Akada's comingout in the eastern parts of the US.
And that's a big deal because thishasn't happened since eighteen oh three and
it's not going to happen again foranother two hundred and twenty one years.
So nationally it's been a bit bigdeal. And for us in Wisconsin,

(01:02):
we only see these insects every seventeenyears, and so that does make it
a pretty rare, unique, amazingnatural phenomenon that the folks have gotten pretty
excited about. You know, whenI first started in you're rite, it
was last winter when I first startedhearing about this, the cicadas, the
broods and all this, all thestuff that I never even knew existed about
cicadas, And I always thinking,well, what's what's the big darn deal.

(01:25):
Don't we hear cicadas about every Augustor so back to school time.
You can pretty much set your watchto it, you can. And these
the catas that you're referring to arecalled our dog days cicadas because they're out
during the hot dog days of summer. They usually start becoming really common in

(01:45):
latter part of July and August.In September, and those are the ones
that make that kind of buzz sawwhining sound during the daytime hours, and
those we do see every single year. Sometimes we simply refer to those as
annual cicadas because they come out onan annual basis. But the ones we've
been seeing this spring and into earlysummer are very very different and the way

(02:09):
that they look, in the waythat they behave and emerge in these massive
numbers and so it's really a coolexperience. And let me ask you the
timing of their arrival. Were theyan indicator that we were going to have
those hot, muggy start to oursummer or can they predict that far out

(02:30):
or what? This is just howthis is just how it so happened to
be that they'd be up here.This is just how it's been with these
particular insects, the periodical cicadas,the timing of their emergence, it just
happens to be earlier in the yearcompared to those annual or dog days aicadas,

(02:50):
which for the most part, areout later in summer. So when
you think about every insect species isgoing to have a little bit of a
difference in terms of timing of whenthey're active and the big periodicals to cada
merchants is really much more of aspring phenomenon. Okay. And now,
so there were two different types ofbroods, but Wisconsin is just getting the
one the brood eight, right,brood thirteen or thirteen? Oh jeez,

(03:16):
I read my Roman numerus from yes, the axis of ten robin. Yeah,
okay, so brood thirteen got itbecause what was the other brood the
other brood to the south of USfrom about mid Illinois on south and across
to the Carolinas and Georgia that wasbrood nineteen, and those have a thirteen

(03:36):
year life cycle. So there's alot of numbers that have gotten thrown out
there between Roman numerals and Arabic numerals. Yeah, and so why wouldn't the
brood thirteen have a thirteen year cycle? That just makes no sense to me.
Well, yeah, so it actuallygoes back to the late eighteen hundreds
and prior to that point, individualsthat were studying these insects had tried categorizing

(03:59):
them. The systems that they hadcome up with just were not great.
And so one particular scientist picked theyear eighteen ninety three and he said,
Okay, if you come out inthis year and you're a seventeen year to
Kita, you are brewed one,and the next year you are brewed two,
And they counted up and up andup and up, and then if
you happen to be a thirteen yearbrood, those would have started with Roman

(04:23):
numeral eighteen counting upwards to nineteen andso on. So it once he had
knowed those details, it makes alittle bit more sense. But if you
haven't heard of that, it doesseem a little weird, like how did
they come up with the names forthese breed numbers? Yeah, I know
it. Well, thanks for someinsight there, because it has just been
driving me crazy as to why it'sthe simplest thing. It seems the obvious

(04:45):
answer would be but yeah, thatexplains it. So now, Cickaita,
is this brood here? Where isthe prime spot? Are they still hanging
around? How long have they beenhere? It hasn't been about a month
now, And yeah it it hasbeen a little over a month now for
areas Lake Lake Geneva. So thefirst report I had heard of in the

(05:06):
state was on Friday, May seventeenthfrom the east side of Lake Geneva.
Things then picked up and really tookoff from there. So Lake Geneva by
far seems to be our single bestspot in the entire state to see these.
And one thing that really stands outis that with the periodical cicadas in

(05:26):
brood thirteen, which again is theseventeen year insects that we have in southern
Wisconsin, northern Illinois, eastern Iowaa little bit in northwest Indiana. They
have a really spotty distribution. It'slike push pins on a map, and
so you can have them in aspot like Lake Geneva, and you can
drive twenty minutes down the road andyou just don't have them. So they

(05:49):
are scattered out there in various spots. Lake Geneva has been great. The
area just northwest of Jamesville has alsobeen great, lots of reports from that
part of the state. And thenelsewhere in southern Wisconsin there have been scattered
reports here and there, but againit's very isolated pockets in southern areas like
Lake Geneva. We're really pass peakand things are on the downswing. There

(06:13):
are still some cicadas out there.I've had reports very recently, just in
the last couple of days, buttheir populations are very quickly dropping off,
and they're going to disappear within thenext week or two. More northern locations
they make it as far north inWisconsin as into parts of Sauk County,
and those might be around for anothertwoish weeks potentially, But in a nutshell,

(06:39):
their days are also numbered, Soare they coming up here and dine
or what They hang out for awhile and then migrate someplace else or what
happens here. Yeah, good question. So they really don't migrate. When
you have them emerge from a givenspot, the adults don't seem to travel
very far. But what's really goingon is these insects have been literally beneath

(07:01):
our feet for seventeen years in alocation where they occur. So they're not
just sitting down in the soil doingnothing or twiddling their thumbs or anything.
They are actively feeding. They havea kind of needle like mouth parts,
almost like a mosquito, that theyuse these to probe into roots of trees

(07:21):
and other plants, and they drinksap that is their food source. Doesn't
really hurt the plants at all.The plants tolerate it just fine. But
during these seventeen years they are belowground, they are feeding, they are
growing, they're developing, they're moltingand getting bigger over the course of time.
And then once you're seventeen coms,the juveniles, which we technically call

(07:43):
nymphs, they come up above groundand then they're going to latch onto usually
or typically some sort of vertical substratethat could be a tree, trunk,
a fence post. You name it. They are going to molt and leave
that old exoskeleton behind and then theytransformed to the adult stage. Once that
happens and the adults are out,they are going to live for about a

(08:07):
month. Now, keep in mindyou have some that maybe emerge a little
bit earlier or later than others.So once the adults start popping out,
it's a period of maybe four tosix weeks and then that's it. Then
they're gone and you won't see thoseadults again for seventeen years. Now.
While the adults are out, theyare making a lot of noise, and

(08:28):
it's essentially all about mating. Themales are making that noise to attract the
female. Yeah, I would sayingthat. That was my next question.
Do they are they like monnies?Is hamersary production. They are in a
nutshell, so that is what allthe noise is about. I went down

(08:48):
to Lake Geneva a couple times tobe able to see these and if it
was a nice sunny, warm day, you would drive into town and just
hit a wall of sound. That'sthe male singing to track the females.
The females can't sing back, butwhat she can do is she can snap
her wings and flick her wings alittle bit. It makes a little bit
of a snapping noise that lets themale cicada know, hey, I'm interested.

(09:11):
They'll have a little a little bitof back and forth singing and snapping
of their wings. They go abouttheir drink, Yeah, exactly, all
that good stuff. So they goabout their business, and then once they're
done, the female goes to treesto lay eggs. And so then those
eggs then do they get absorbed downin the ground or Yeah, that's another

(09:37):
great question. So what the femaledoes is she has this egg laying device
which literally looks like a spear ora needle under the microscope, and she
takes that she cuts these little slitsinto twigs and small branches. She inserts
these eggs into those twigs, andthen it takes about six or so weeks,
so about a month and a halfish to maybe upwards a two months

(10:00):
for those eggs to hatch, andthen the really tiny juveniles are literally going
to rain down to the ground.So this would be going on in probably
July or so, and folks haveprobably forgotten about cicadas because they've been quiet
for so long, and they're probablygoing to miss these little juveniles raining down
to the ground. Once they getto the soil, they're going to burrow

(10:22):
in where they're going to spend youknow, ninety eight percent or so or
their life blowground. Creepy yet fascinating. Now, have you ever Yeah,
I'm sure with all the Cicada Paloozafestivals and just all the excitement surrounding these
critters, I'm sure you've heard abouteating them. Have you ever tried one?

(10:48):
I have? Yeah. So wedid host an outreach event down in
Lake Geneva back on June eighth calledCicada Palooza, And this was an event
to simply celebrate this amazing natural phenomenonbecause you know, if we only have
them every seventeen years in the state, you might have three, four or

(11:09):
five times in your entire life tosee them in Wisconsin, which is pretty
cool. They are edible, Imean, in terms of their ecological benefit.
That's probably the biggest thing they dofor wildlife is serve as a food
source. They are very palatable.All sorts of wildlife is feeding on these,
but they're also edible, you know, humans can have them. For

(11:31):
our event, we did partner withsome local groups that prepared, you know,
little things that folks could try.A local restaurant prepared some desserts and
little kind of appetizer plates. Andthere was a cicada gumbo. So this
was relatively small numbers as a cadasthat were used to make this. But
if you think about it, youknow, you or I might go to

(11:52):
a restaurant and pay a lot ofmoney for crab lobsters, and folks are
sometimes kind of squeamish about the ideaof insects, but evolutionarily speaking, they
are very closely related to the seafoodthat we'll pay a lot of money for.
Yeah, you're right, and youthink about like crawfish, that's you
know, that's a staple down south, and crawfish are just kind of just

(12:15):
big bugs when you think about it, right, exactly exactly. So I
did get to try a little bitof the cada food. And there was
also a brewery in Lake Geneva thatcrafted brew a beer that had some dried
the catas in it for the brewingprocess. So does it taste like chicken

(12:37):
or what close what flavor closely resemblesor does it have something so unique you
couldn't you couldn't describe, you know, I would say, really it was.
It was fairly subtle, perhaps alittle bit of earthy or nutty taste
to them. But in the likethe food items that I had, it

(12:58):
would remind me if you just hadlike a small shrimp that was fried up
really crisp. Is probably the bestanalogy that I thought of. Yeah,
actually, maybe then I would trythat because I adore shrimp as many people
do. All right, So cicadas, So yeah, sokk, the furthest

(13:18):
north you've seen at Sauk County orthe furthest they've been reported, and they
might have another month of the seasonthen and then that's all she wrote.
Well, and not even that muchfor Saw County. It might be a
couple more weeks, maybe twoish weeksor so. And this isn't going to
throw off the dog cicadas, isit? They're going to come out in

(13:39):
August or because of our warmer,humid weather. Do they are they timed
to a certain point or is itdriven by the weather. Well, it's
driven by weather to a certain extent. And in general, insects, essentially
being cold blooded creatures, weather hasa big impact in terms of temperature,

(14:01):
and so the hotter things are orthe warmer things are, that can kind
of speed up emergence. And intuitively, you know, we see and observe
this every single year. If wehave a warm spring, we are going
to you know, understand that plantsare emerging earlier. That's just kind of
that whole field of phonology. Andthe same kind of thing can happen with

(14:22):
insects. And so there's a moretechnical way that scientists can tract this,
using something called growing degree days.It's basically a mathematical way to kind of
gauge and count how much heat you'veaccumulated above a certain threshold, and most
insects it's got to be above aboutfifty degrees and so there's a mathematical way

(14:43):
to do this. But in general, when I've looked at those numbers,
you know, we've been perhaps alittle bit of ahead of kind of the
long term average this here. Soit wouldn't surprise me if things like those
annual dog days of cadas popped outperhaps a week or so ahead of normal.
But for the most part, it'snot going to throw off their life

(15:03):
cycle much at all. And dodo they pinch or do they do anything
if you pick it up. Theperiodical skads know, they are really surprisingly
docile. When we had our bigoutreach event down in Lake Geneva, we
were picking these up during a guidedwalking tours just to show them off to
individuals and point out various parts ofthe anatomy. And they are really pretty

(15:26):
docile. They tend to just kindof sit there. If it's a male,
they might produce a little bit ofsound perhaps, you know, if
it had been a predator grabbing them, that might be a last gasp effort
to perhaps startle predator. But otherwisethey're really quite harmless creatures. And now
the DNR had to put out peoplewere taking them from state parks. It
just probably isn't a good I mean, if you take them home, what

(15:50):
you're going to kill it, right, because it's out of its habitat well
right, I mean, these thingsdon't live terribly long to begin with,
so it's not the type of creaturethat makes a great pets because adult lives
maybe a month or so. Theydo need to be around trees. The
adults will feed a little bit moreof ingesting fluids perhaps for hydration and some

(16:11):
other things. But again they justdon't make great pets. And I think
it's great that folks really became interestedin these insects this year and gave them
a lot of attention. I knowa lot of kids came to our event
and were at just about it.You know, if you have one as
a pet, that's one thing,but when folks are collecting just massive numbers
of them, that's a little unfortunateto hear about. And our severe weather,

(16:37):
our a series of tornadoes and storms. Does that impact the population or
are they pretty resilient that sort ofthing. Yeah, that's a great question,
and it'd be really hard to tell. I suspected it wouldn't have much
of an impact on them. Atthis point, they are mostly done for
the season, so I know.Unfortunately, Lake Geneva had some severe weather

(16:57):
just in the last week or so, including some tornado like activity down there,
But at this point, again,most of the mating is done,
the eggs have been laid in twigs, and so I suspect from that standpoint
the weather probably wouldn't affect them muchat all. Okay, I'm going to
I'm going to save the best forlast. That's the scorpion discovery. But

(17:21):
We're gonna move on from the cicadasbecause there are so many different species to
delve into here. Now, let'stalk about spongy moths. I read a
piece here that an invasive species thatthey're dying off in large numbers. That
should should that be considered good newsor not? And if not, why

(17:44):
not? I think it is certainlygood news. I mean this spongy moth,
which years ago folks had maybe heardit by another name of gypsy moth,
but that name is no longer used, So the spongy moth, it's
an invasive species. It can bevery destructive. They feed on a very
wide range of landscape and forest trees. They really love oak trees, for

(18:07):
example, but they can feed onhundreds of different types of plants. And
in the state as a whole,we have been experiencing an outbreak of these
Their populations have been building up overseveral years now, likely due to some
of the dry spring weather that canreally help them out. And so we're
at the point where really we coulduse a break here from these insects.

(18:30):
They've been wreaking a lot of havocon trees, and you know, if
you have a healthy tree and itgets defoliated in one year, it's most
likely going to be fine in thelong run. But if that seam tree
gets defoliated again and again, thensecondary issues start to pop up. There's
a wide range of opportunistic secondary insectbores and things like that that can get

(18:52):
their foot in the door, andthen it's a slippery slope and those trees
can just decline. So this yearit's great we're getting the rain that can
help out trees because they have sufficientmoisture. But also when you have lots
of rain, that can encourage afungal disease that specifically infects and kills these
caterpillars. So there's that going on. There's also, due to crowding in

(19:15):
their populations, a virus that isinfecting and killing them too. So I've
been out in the field just inthe last couple of weeks and I've had
lots of reports come in, andI know colleagues at DNR and Department of
Agriculture are getting lots of reports aswell of dead, dying, spongy moth
caterpillar. So it's certainly a goodthing for us in the state to give
a little relief and allow those treesto recover. Yeah, that sounds like,

(19:37):
well good, that's good news tohear. Unfortunately, though, well
they're dying off. The Japanese beetleseems to be doing just fine, if
not flourishing this year. Huh.Yeah, well, we're still a little
early to tell for Japanese beetle.One thing that still has me scratching my
head. I received my first reportof a Japanese beetle from back on June

(20:00):
second, which is the earliest Ihave ever seen them. That right,
It was, Yeah, so justwest of Madison, about fifteen minutes or
so. In a usual year,the first report I get will maybe be
second third ish week of June,and as we get into July, that's
really when Japanese betle season takes off. So I had that one early report

(20:25):
and I thought to myself, ohboy, this could be a you know,
potentially a rough year. But it'sbeen early quiet since then. Oh,
I am expecting just it could beany day now that we're going to
start seeing more of these. Forsouthern Wisconsin. I'm not expecting a particularly
bad year simply because the last fewyears their populations have generally been down in

(20:47):
the southern part of the state.But if they have sufficient moisture, because
they like to go and lay eggsin lush, green lawns. If the
rains continued, they might have goodconditions, and who knows, maybe they're
population will build back up for futureyears. But you know, how will
the Japanese beetle season b ultimately,Well, we're going to start finding that
out here in just the next weekor two. I feel is that the

(21:11):
same species of insects as the Asianlady beetle. No, they have similar
sounding names, but they're actually completelydifferent families of beetles. Okay, what's
the flying one that it covers likethe back walls of homes, doors,
anywhere there's moisture they like to Yep, So that would be the multi colored

(21:33):
Asian lady beetle, or sometimes justcalled the Asian lady beetles. And yes,
yeah, the Japanese beetles are kindof a coppery brownish color and green
little whitish spots, and they loveto feed on a wide range of plants
in your yard and garden. TheJapanese beetles they really don't have any interest
of coming in your house. Butboy, if they're abundant. They can

(21:56):
really do a number on the plantsin your yard. Yeah, absolutely,
all right, And again I'm talkingwith UW Madison entomologist PJ. Leash about,
of course the cicada invasion and theother the bugs scene this summer here
in southern Wisconsin. We have afew more minutes left here and the boy,
this really raised an eyebrow when Isaw this, that there was an

(22:21):
actual scorpion that was found here inthe Madison area. Some guy watching TV
and out of the corner of hiseye see something moving and it's a scorpion.
That just wow. Yeah, andthat really was a curveball. I
was not expecting that. So mymain role here at UW is to run
the UW Insect Diagnostic Lapse. Soin a nochell, I help identify insects

(22:45):
in related creatures for people. Itcould be a farmer or a home gardener,
or just someone that finds something intheir house. And so as you
describe individual was in their basement watchingTV. They happen to see something moving
it ended up being a scorpion.Now, at this point I've worked with
it enough under the microscope, I'venarrowed it down to a group of scorpions

(23:06):
that occurs in the southern US andparts of Mexico, and some of the
species for this group do make itactually as far north as into parts of
the eastern US, such as Kentuckyand Virginia. We don't natively have scorpions
in Wisconsin, but some species inthe group can make it a little bit
farther north. But how did itget here? I still don't know for

(23:30):
sure. You know, it probablyhitchhiked, either in a vehicle or in
goods that have been shipped around.But in my ten plus years here in
the diagnostic lab, I think thisis only the third time that I've had
a scorpion come through my lab doors. Wow. And I mean, is
this the type of scorpion that wouldbe deadly or all scorpions deadly or just

(23:52):
certain just certain ones. And sothat was one thing I was really curious
about. Of course, there aresome scorpions that are much more medically important
than others. A lot of thespecies in the US, for the most
part, if you were to bestung by them, which would be pretty
rare, it would be a localizedreaction similar to a bee or a wasp.

(24:12):
So not particularly concerning, and basedon what I narrowed down the identity
to it, it was a speciesthat wasn't a medical concern at all,
but again still something that was abig surprise for the individual that brought it
in. Yeah, and just creepylooking little things. I suppose in the
eyes of an entomologist, though,you find beauty and everything, and you

(24:34):
probably think it's quite breathtaking. Yeah, I would say, I do really
cool to examine it up close underthe microscope, because I don't get many
opportunities to do that. Yeah.And it's how long do they live?
I mean, because you don't wantit. You're doing what you can to
keep it alive, right, justso you can study it well. In

(24:55):
this case, the specimen was actuallydead when it was brought in. If
it had been, I probably wouldhave tried keeping it alive, but in
this case it was a preserve specimen. Did the guy kill it? Yeah,
yeah, I think I would too. I can't blame them, you
know, you stomp first in questionlater when you see something creepy crawling in

(25:17):
your basement, you know. AndI'm actually surprised. I'm relieved, but
I'm surprised that you haven't come acrossmore of these with Amazon and the delivery
I mean things just over the pastcouple of years anymore, as everything is
being shipped from all over. Yeah, I mean, it's really interesting when
you look at even the bigger picturesince World War Two, the amount of

(25:41):
global trade going on with you know, containerization and shipping and stuff like that.
As humans, we are moving alot more stuff around the globe compared
to one hundred two hundred years ago, and that means species can get moved
too. With hearing in the newsabout juro spiders and you know, the
so called murder hornets and that we'rein the Pacific Northwest and thinks like that.

(26:03):
So humans are really good at movingsome of these things around. I
will say, I do see everyyear a few things where you just kind
of scratch your head and say,that must have been, you know,
shipped with goods from somewhere else.Sometimes certain cockroach species that we really don't
have here in Wisconsin or are reallyrare and are much more common in warmer

(26:25):
areas, and you just think toyourself, you know, this must have
have hitchhiked or someone traveled elsewhere tothe Caribbean, or something like that,
and some hitchhike back from warmer locations. So it does happen and again,
and we as humans have made itpretty easy for some of these creatures to
be moved around. Are there anyredeeming qualities of a cockroach? Yes,

(26:47):
actually so if we look and youknow, as most folks, they're going
to have a negative impression of cockerand I can understand that. But when
you look at the bigger picture,there's thousands of cocker species around the planet.
There's probably let's say, about twodozen or so that give the rest
a bad rap. It's that smallsubset that can live in and around human

(27:11):
dwellings that people really don't like.The vast majority of roaches are really beneficial
recyclers, if you will. Theyare creatures that could not survive in your
house if they wanted to. It'sjust too dry for them, not the
right conditions. These are creatures thatlive out in like rotting logs in the
woods, and they help break downdecaying plant material and return those nutrients to

(27:34):
the ecosystem. So they're really quitebeneficial in that regard. And along those
lines, I mean, we havesome roaches like that here in Wisconsin that
we call our wood roaches. Youhave to go out in the woods,
say up in the Baarboo Hills.You kick open a rotting stump or peel
bark off a fallen log. That'swhere they live. Those insects could not

(27:56):
survive in your house if they wantto, and they're just out in the
ecosystem playing their role. And also, I mean they are a food source
for other things in the ecosystem too, so there can be a couple redeeming
qualities to them. All right,And as we're getting close to having to
wrap it up here, by theway, you're a fascinating interview. Thanks
so much. I really appreciate youjoining me, and we'll have to talk

(28:18):
again. What's your favorite bug?Oh, that's a tough question. I
mean, in Wisconsin we have somewherein the ballpark at twenty thousand estimated species,
and worldwide there's over a million.As a whole, I love beetles,
but worldwide there's over four hundred thousandbeetles species, so even then it's
hard to narrow down one. Butone insect that really stands out to me

(28:42):
this year would be periodical deicatas absolutelyfascinating. But then one other one I
would love some data see in itsnative range. It's called an ice crawler.
These live in parts of the westernUS up into Canada, around into
parts of Siberia and Japan, andsome of the species live up on glaciers

(29:03):
and permanent snowfields in the mountains ateight ten thousand foot elevation. They live
on the ice and snow and ifyou were to pick them up and hold
them in your hand, they woulddie. It's simply too warm for them.
So these are really cool, fascinating, quirky insects that just live in
these very extreme environments and they comeout at night and they just scavenge for

(29:26):
dead insects that have fallen on thesnow. And so I've been out west
looking for them. Haven't seen themlive myself out in nature, but I
would love to do that someday.Well, I wish you luck in your
search. PJ. PJ at leashmy guest again this morning, UW Madison
Entomologists. You've been listening to MadisonForum. PJ. Oh my gosh, you're wonderful