Hello everybody I am new to reptile boards and I've got a question and am wondering if anybody can help me out/give me advice about my hornworm pupae. I originally started with 9 hornworm pupae and after about 4 weeks 1 moth emerged (which I'm pretty sure is a male). Also I have 8 other ones from which the moths have not emerged. This I my first time rearing hornworms and with the pupae over time I have seen a significant darkening of shell. What I'm wondering is this normal? The first to emerge pupae was like this but I'm wondering why these are taking longer (6 weeks almost) I'm wondering if and when these hawkmoths will emerge and if they may have entered diapause. They're still gradually darkening and are becoming delicate and crunchy but enough to remain intact. I've also seen the thorax of the moths recede and shrink in the cocoons. Their is no foul odor so I'm assuming they're still viable and close to hatching but am not entirely sure. Let me know if this differs from any of your experience and any other help/advice on raising the eggs/larvae would be greatly appreciated. Also am currently incubating some silkworm eggs and am wondering if the husbandry is similar to that of these silkworms (beside the diet!) Also the pupae will move from time to time if disturbed but I have seen a large decrease in activity.
Hi Godzilla1487, welcome to the boards! What are the conditions you are keeping your hornworm pupae under? What temperatures, day:light cycle, and are they buried in substrate or not? Insect development is influenced by temperature, light, and relative humidity. Also, particularly in the pupal stage, there are temperature thresholds in which development may proceed or halt. Too cold and they may enter diapause, too hot and you can see development issues and death. I'm not going to lie, it has been a long time since I've reared either hornworms or chinese silkworms, but I would be happy to try and help with your questions when I can. 6 weeks seems like a long time to be in the pupal stage from what I can remember; maybe your temperatures and day:light cycles are off or there is some other minor husbandry factor the insects are sensitive to. I don't recall how coloration or morphology changed over the course of pupal development either [ sorry =( ]...Regardless, I would continue to care for them until they either certainly perish or eclose just to be safe. I'll also ask a Lepidopterist friend to see if she has any experience with what you're observing in your pupae. Silkworm larvae can be reared much the same as hornworm larvae. The major differences occur in the pupal and adult stages, where hornwom larvae usually require a substrate to burrow into to encourage pupation and silkworm larvae will be content using toilet paper rolls during their wandering stage as a pupation location. Silkworm adults (moths) do not fly and are incredibly easy to breed in a small area. Adult sphinx moths require space and host-plant volatiles in order to induce laying (Solanums: Tomato, Pepper, Tobacco plants, etc.) The moths will lay eggs either on the plant directly which will need to be removed prior to hatching or may lay on other surfaces in the enclosure if host-plant volatiles are strong enough to encourage it (I used a large screen/mesh cage for breeding with a small host-plant inside). It may even be possible to place the host plant species outside of said screen cage with various cardboard structures within and this may be enough to encourage the moths to lay on surfaces within the cage (speculating). Both species have artificial diets available. As I'm sure you know, Mulberry is safe to feed to silkworms as long as it was collected from a safe source (no -cides) and can still be fed to herps on this natural diet. Hornworms sequester their host-plant toxic metabolites, such as nicotine or cardiac glycosides from their Solanum host plants (Solanaceae is the nightshade family, many toxic plants used by hornworms as host). Therefore, never feed wild caught hornworms and never feed hornworms that have ever taken a bite out of a host-plant even in their earliest developmental stages. Let me know what conditions your are keeping the insects in and we can try to go from there. I may be able to help more with specific husbandry related matters for the larvae and adults. I will help when I can, but I'll be pretty busy this week... Trying to finalize a proposal to conduct research on parasitoid wasps closely related to the Braconid species that parasitize your hornworms in nature
Also - a little tip for rearing larvae. Depending on the quantity you are rearing, I would recommend one of the following options: A) Rear smaller groups in cups much like those sold by Mulberry Farms and the like, in which the food product is kept at the top of the container/cup. This allows frass and molted skin to fall to the bottom where you can simply open the lid and let the majority of it roll out. Helps to keep things a little more sanitary. http://www.mulberryfarms.com/Hornworm-Cup-Green-Food-p23.html B) For larger quantities, I've had great success elevating plastic grating in a plastic container as a surface for the larvae to live on. I don't recall the exact measurements of the grating I used ('hole size') for each instar but you cay buy it pretty cheap. It works particularly well for larger, later-instar larvae whose frass accumulation becomes a problem. The grating should be large enough for frass to fall through, but small enough to keep chunks of food and larvae from being able to pass through. Basically, instead of a smooth, uniform surface that accumulates all old food debris, skins, silk and frass; you create a surface for larvae to live on and feed on with their waste products falling down to a lower level inaccessible to them. Let's see if I can make this work by "drawing" and image with the keyboard. Your enclosure (Imagine a border on the right side as well): I I I- - - - -- - - - I <- The larvae live on the grating (dotted line). I I_____________I <-- The lower level allows for frass and waste accumulation that passes through the grating.
Thanks for all the helpful advice! to answer some questions the light cycle is 14 hours of daylight and they're in a vertical 40 gallon tank (as my veiled chameleon owns my only sceen cage haha)! Also they are not buried but at one point were for pupation. I mist then every other day and is it important to let them remain buried? I reared them in the cup as you explained, but planned go raise the later instars of this batch (if the other pupae hopefully hatch) in the shoebox containers with the elevated screen to let the frass fall through. I have a medium size tomato plant I've been growing to allow the moths to lay their eggs on but the plant is not currently in their cage. I also have two small tomato plants and a pepper plant growing . Also I have a pound of silkworm food and a pound of hornworm food (dried) in my fridge. Not sure how long that'll last! Again I will let you know if I'm in need of more advice! I think what you've explained to me was more than helpful and I hope you proposal goes through to get that research done! Thanks again.
Thank you! =) We'll see how the pupae turn out - I may have a chance to talk to that Lepidopterist today for some additional input. I'm purely speculating here, but I don't think you want to mist the pupae directly... not sure if you are or not, but the key is maintaining the right level of relative humidity. Too much moisture on the pupae itself may be bad news... but again, I'm only speculating.
