Category: Unidentified_Diptera

V. atalanta Rearing Notes (8/20/16-8/27/16)

8/27/2016

The fourth installment of rearing notes for Red Admirals (Vanessa atalanta) that we collected at Tilden Regional Park (Berkeley, CA) from 8/20-8/27.

Rearing Notes and Stats 8/20/16-8/27/16:

8/27:

The second instar is growing well

8/26:

The first instar has molted to second and is pitch black (top row)

8/25:

The first instar is now in apolysis for second

8/24:

No new eggs hatched, but the first instar is growing well; it likes to curl up the leaf with its silk

8/23:

Another one of the chrysalises turned out to be parasitized by a tachinid fly
Currently two prepupae, one fourth instar in apolysis for fifth (second row left), one fourth instar, one third instar in apolysis for fourth (second row middle) and one third instar (second row right)
The newborn is eating and growing very well; it has already built a nice nest made from silk attached to the surface of the leaf cutting

8/22:

One of the eggs that we collected on stinging nettles (Urtica dioca) at Tilden hatched sometime this morning; it appears to be a Red Admiral and not a Satyr Comma (Polygonia satyrus) since by nighttime, it had already built a loose silk shelter (left) and the latter species only construct nests in the later instars

8/21:

A newly molted fourth instar has died (first row left)
Found a second and third instar at Tilden as well as three eggs (first row middle)
Two third instars in apolysis for fourth (first row right)
One of the chrysalises was parasitized by a tachinid wasp (second row middle and right)
Some eggs becoming pharate (last row)

8/20:

Two of the fifth instars have pupated

Stats:
Encounters this year:

Eggs (21) Difficult to identify whether they are Red Admiral or Satyr Comma
Larva (21)
Pupae (1)

Locations:

Tilden Regional Park District, Berkeley, CA (E21) (L21, P1)

Months:

July (E19) (L10, P1)
August (E2) (L12, P0)

- Brian

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Gulf Fritillary Tachinid Fly Emerges

8/8/2016

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Today, the first of our many tachinid fly (Tachinidae) pupariums emerged. It originally parasitized one of our Gulf Fritillaries (Augraulis vanillae).

On 7/2, we found out that one of our wild caught Gulf Fritillaries was parasitized. Three maggot bit their way out of the chrysalis and pupated. They were huge pupa, quite obviously some kind of tachinid fly and not a parasitoid wasp which are often much smaller and come in huge numbers.

For such a small insect, it would be logical to assume that the tachinid flies have a fast life cycle. We expected that the pupariums eclose within a week or two. But it took over one month for even one of them to emerge! We're not even sure whether the other ones are even still alive (we have gather quite a lot of them from outer wild caught chrysalises over this past month) or they really do take such a long time.

After the fly emerged, we put it in the freezer. The scary part about parasitoids is that they look surprisingly similar to their non-parasitoid counterparts, just usually smaller. This tachinid fly has the same basic appearance as any other harmless fly you see around. This makes it just the more important to keep the pupa after they come out so you can see and document what they eventually become for future reference!

- Brian

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A. vanillae Rearing Notes (6/28/16-7/12/16)

7/12/2016

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The second installment of our rearing notes for the Gulf Fritillary (Augraulis vannilae) from 6/28-7/12 obtained from both wild caught and captive produced eggs.

Rearing Notes and Stats 6/28-7/12:

7/12:

One of the wild caught fifth instars has formed a J

7/11:

The wild caught fifth instars are very large now (shown below)

7/8:

Collected 2 eggs, 2 fifth instars, 2 fourth instars, and 1 second instar on the passionflower at the Ohlone Greenway at Lincoln Ave., El Cerrito; caught a male butterfly with our new butterfly net; found a parasitized chrysalis
Most have molted into fifth instar at home (a fifth instar is shown below); moved them in pairs into larger petri dishes and put the wild-caught fifths in the chrysalis enclosure

7/9-10: Nothing significant worth noting.

7/7:

Now molting into fifth instar (first row left and middle shows a fourth instar in apolysis for fifth; the other images are of a newly molted fifth instar)

7/5-7/6: Nothing significant worth noting.

7/4:

Most are fourth instars and seem to have a lot of red relative to the black; are eating a lot (some shown below)

7/3: Nothing significant worth noting.

7/2:

One of the four chrysalises (the first one) was parasitized with three maggots crawling out and forming pupa; not too surprised since the chrysalis was undersized

7/1:

Many are starting to molt into fourth instar now

6/30:

All four of the fifth instars have now pupated
Noticed some possible cannibalism in one of the enclosures despite there being plenty of food; two of the caterpillars were away from the leaf and one of them appeared to be severely injured (losing entire abdomen)

6/29:

Total of 18 caterpillars (from egg); we have separated them by size into two enclosures () of 9 and 9
One of the fifth instar prepupas has pupated
Third instar caterpillars now in apolysis for fourth (shown below)

6/28:

All three other fifth instar caterpillars have now formed a J

Stats:
Encounters this year:

Eggs (2)
Larvae (6)
Pupa (3)
- live (0)
- dead/emerged (3)

Locations:

Ohlone Greenway at Lincoln Ave., El Cerrito, CA (E4, L11, P4)

Months:

June (E2, L6, P3)
- first instars (1)
- fourth instars (3)
- fifth instars (2)
- Adult - numerous; many times per week even occasionally in the city; often 3-4 around passionflower
July (E2, L5, P1)
- second instars (1)
- fourth instars (2)
- fifth instars (2)
- Adult - less common than before; possible once per week in the city; occasionally 1-2 around passionflower

- Brian

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One of the Wild-Caught Gulf Fritillary was Parasitized!

7/2/2016

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Today we witnessed three huge tachinid fly (Tachinidae) larvae crawling out of one of a Gulf Fritillary (Augraulis vanillae) chrysalis from a wild-caught caterpillar.

Virtually every species of caterpillar have natural parisitoid enemies. Some species are routinely parasitized such as Monarchs (Danaus Plexippus) with tachinoid wasps (Tachinoidae) while it can be rare in other species. For the record, we have never had any problems with wild-caught Gulf Fritillary (Augraulis vanillae) caterpillars being parasitized -- until today.

Today we had the honor of witnessing three ridiculously fat maggots eating and crawling their way out of our oldest Gulf Fritillary chrysalis that pupated on 6/29. The chrysalis was made by a wild-caught caterpillar that we caught in fifth instar which we noticed was significantly smaller than the three other wild-caught fifth instars we had (so far, we don't think these three have been parasitized). Being undersized is a typical symptom of being parasitized for pretty obvious reasons -- they are being eaten alive by the parasites!

After the maggots came out, they hardened into extremely round, dark brown pupariums. There are endless species of parasitoid wasps and flies (order Hymenoptera and Diptera) and it is close to impossible to identify them down to the exact genus and species until they emerge, and even then it is difficult. But we can say pretty safely that they are probably just tachinid flies since parasitoid wasps rarely get this big. When they emerge a week or so later, we will be sure to take some more pics and report back!

- Brian

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