Deloyala guttata are magnificently beautiful little beetles, about 5mm long, similar in size to some native species lady beetles, but smaller than the common non-native Harmonia axyridis and Coccinella septempunctata. I've raised multiple generations of these guys in order to observe and learn more about them.
Here I will briefly discuss 1) Finding the beetles, 2) Housing, 3) Life Cycle, 4) Care, and 5) Observations.
Finding Deloyala guttata
The best way to find Deloyala guttata is to find Ipomoea or Convolvulus species (Convolvulaceae family) growing in a natural area and then to look for well-munched leaves.
Morning glory (Ipomoea cordatotriloba) and well-munched leaf:
(Note: the image below is from my own garden so the leaves are much more heavily munched than what would be found in natural areas where the beetles would spread out more.)
The beetles might be on the Ipomoea/Convolvulus plant (generally on the underside of leaves or on stems) or they might be resting on a nearby plant. The first one I found was on Turk's Cap (Malvaviscus arboreus var. drummondii), but there was Ipomoea cordatotriloba growing nearby.
I use plastic food containers of various sizes to catch most of my creatures. With these beetles, I clip off a bit of the stem with the beetle or, if on a large leaf or near the bottom of the plant, I just clip the leaf with the beetle. These beetles are generally fairly chill so it's easy to place the plant cutting with the beetle on it into a container. For Deloyala guttata, I use 4" x 4" containers (10cm) so that I can get them comfortably in the container with a cutting of their host plant.
Because it's very difficult where I am to find Ipomoea or Convolvulus growing in natural areas, I rarely see this beetle. They are likely quite hyperlocalised. I did find one local park garden with morning glory before the park manager discovered and destroyed the plant. Before that, I was able to find around a dozen Deloyala guttata whom I brought home to raise.
Housing
To raise these guys, you simply need a good, steady supply of organically grown host plant and a nice cage. For these beetles and most other creatures I raise, I use large butterfly cages (36-inches tall; floor of 24" x 24").
I add 4-inch pots of their host plant. In this case, I used Ipomoea purpurea because I had read that the species likes it and the seed is easily obtained online. Fortunately, the plant is surprisingly easy to grow. It germinates quickly and grows fast under grow lights. Larvae and adults eat a
lot of the host plant, so you'll need to start new seeds regularly.
When I first started, I pulled some Ipomoea cordatotriloba and Convolvulus equitans (Texas bindweed) out of the ground with roots and simply started those. The plants were rather messy starts, but it served my beetles well until I was able to grow a good supply of my own. The beetles adapt easily to different species of morning glory varieties.
Life Cycle
My Deloyala guttata wasted no time in mating.
Unfortunately, I was never able to photograph eggs.
The youngest larvae are quite small and generally can be spotted by their fecal shields (the shield of feces and exuviae that they carry, apparently to deter predators. (See
Effectiveness of Tortoise Beetle Larval Shields Against Different Predator Species.)
On this leaf (underside), a tiny larva can be seen to the left of the vein toward the middle:
These larvae have recently hatched (about two weeks after the adults first mated):
These larvae are a bit older:
Here's a closer image of an early-instar larva:
The larvae spread out quickly, especially the more they grow. (They might go through five instars? I never saw one moult.) They munch more deeply into the leaves. They are gentle and play nicely together.
Here's a middle-instar larva:
And this is a final-instar larva with an exceptionally handsome fecal shield:
When pupating, the larvae fold the fecal shield forward over their bodies. The fecal shield will be part of the exuvia. (This is different from Gratiana pallidula who shed the fecal shield before pupating.)
Deloyala guttata in final instar and then in pupal stage (3 days later):
Deloyala guttata one day before pupating (prepupal) and one day after pupating (pupa):
Deloyala guttata pupating:
Handsome Deloyala guttata pupae:
and
Ventral view of 4-day-old pupa:
This Deloyala guttata is ready to eclose. The translucent pronotal hood can be seen here:
Here is a freshly eclosed Deloyala guttata with exuvia:
This series show the pupa eclosing to full adult with the exuvia over a one-day period:
Care
Caring for handraised Deloyala guttata is quite easy. You should provide a large cage and plenty of host plant. Water the plants and keep the cage clean. I put newspaper at the bottom of my cages and change it out regularly. Deloyala guttata when healthy young adults will fly, so be very careful when opening the cage. For safety, I generally keep host plants toward the back of the cage. You will likely find some adults and even some larvae on the walls or ceiling of the cage: this is normal. It's likely that larvae are moulting on the walls of the cages, and some of the beetles pupate on the side of the cage.
Caution: Be especially careful when unzipping any butterfly cage containing creatures, as creatures often hang out on the zipper, regardless of type of bug.
Observations
Life Span and Orangie:
These guys seem to be hardy beetles. The ones whom I overwintered through 2020 are still alive, eating, and mating as of May 2021.
Update: My final beetle who eclosed in early fall 2020 died on 07.09.2021, having lived as a full adult for ten months (!). Several others lived well over seven and eight months as full adults.
An orange mystery: One guy in the cage (and only one) eclosed as a beautiful orange. I mistook him for a colour variation of D. guttata and he was perfectly happy with his Morning Glory plants. I named him Orangie and since he was my only orange specimen, I was able to observe him individually. Orangie eclosed on July 8, 2020, and died on February 12, 2021, living as an adult for over seven months (!!). Only after that did I learn from "bugidentifier" here that Orangie was in fact Jonthonota nigripes. He's the only one of this species that I've ever seen. The very few Texas records seem to have them mostly in Dallas. I still can't figure out how he ended up in my Deloyala cage, but I guess the larva was on a wild Convolvulus that I brought home before I started growing my own from seed. Unfortunately, wild Convolvulus is very difficult to find where I am.
Here's Orangie just eclosed, then at two days (middle two), and at five days:
Geriatrics:
My very old Deloyala guttata no longer fly. They are able to crawl, but sometimes fall. If they land upside down (very rare with this species), I have to turn them over. Other than that, the ones I have raised often live more than seven months as adults. While they continue to mate in old age, they no longer reproduce.
Fecal Shield:
On a few occasions when I had to move larvae onto fresh plants, I accidentally broke off the fecal shield. The good news is that within a day or two, the beetles are able to recreate the shields as good as new!
(The easiest way to move larva is to gently "scoop" them up from the back so that they curl the fecal shield over their bodies and then stick to your finger as you roll your finger forward. They are good at sticking to surfaces. I then put them on a new plant and curl my finger back towards their rear so they can climb onto the leaf. With tiny guys, I used toothpicks.)
Flight:
Deloyala guttata can fly quite well. In my large cage, however, they generally did not try to fly out, likely because there was plenty of host plant, available mates, and the cage was not overcrowded. Like other beetles, these guys will drop if threatened. They also curl their legs and antennae under them when disturbed. The easiest way to pick one up off the floor of the cage when he is curled up is to slide a small strip of paper underneath the beetle. Once they are put on a horizontal leaf, they generally extend their legs and hold on quite well. (Other beetles I've raised sometimes "play dead" for much longer and refuse to extend their legs to grasp the plant.)
Questions:
1. The specific epithet "guttata" means spotted, but what does the genus name Deloyala mean? I cannot find an answer to this. One non-entomologist friend, Tom McIver, suggested that perhaps French entomologists Dejean and Chevrolat sought a Catholic name and used a variant of DeLoyola, Ignacio de Loyola, priest and co-founder of the Jesuits. Tom photoshopped an image depicting his surmise;
2. Why can't I see eggs? I see the tiny larvae, but so far I've never seen eggs on leaves.
Edit: Answer -- I didn't know until I started raising Gratiana pallidula that the eggs are actually enclosed in oothecae. I wasn't expecting that, but now I know what to look for.
3. Morning Glory here is slow to come back after winter (one of the later-emerging plants). Are Deloyala guttata capable of eating anything else beyond Convolvulaceae?
Edit: My guess: very unlikely. The ones I raised went into extended diapause over winter and did not become active again until spring.
A few articles:
Conditioning and genetic variation as causes of individual variation in the oviposition behaviour of the tortoise beetle, Deloyala guttata
Life Cycles, Mating, and Color Change in Tortoise Beetles
Effectiveness of Tortoise Beetle Larval Shields Against Different Predator Species (referred to earlier)
The diversity and specificity of parasitoids attacking Neotropical tortoise beetles (Chrysomelidae, Cassidinae)
