Someone in Mt Roskill reports:
"When My catapillars almost gone from unknown invaders, I saw a mice run around the swanplants. I set a mousetrap beside the swanplants and after traping the mouse, the rest of catapillars never had gone."
Another pest to add to the list!
Mice will take pupae and adult butterflies also. One morning several years ago I went into my shade house to see if my Yellow Admirals had oviposited. Looking around I could only find 4 of the butterflies, 10 being there the previous night, so I began moving potted plants around and found a pile of wings and mouse droppings. I had also previously noticed some of the larvae missing but assumed they had gone off to pupate. So I set a mouse trap that night and next morning found the mouse in it so I set it again. Over the next few nights I caught mum, dad and two siblings and lost no more butterflies. The butterflies roosted for the night on the wall of the shade house which was easy for the mice to climb. Subsequent visits at night to experiment showed that the butterflies could be picked off their resting spot without seeming to disturb them, so it was easy for the mice looking for a good source of protein. So be aware that if you spot wings and nothing else on the ground it is usually mice or praying mantids. Ants will take a while to dispose of a complete body and they are usually seen coming and going.
Hedgehogs will take larvae and pupae, but the butterflies normally roost too high for the hedghogs to reach.
The monarch butterfuly (Danaus plexippus) is not at all nice to eat. In fact, its chemical defences are so effective that a predator stands a good chance of dying a horrible death, sometimes in mere minutes. Despite this, however, one species - a mouse that lives in Mexico - has adapted so that it can live exclusively on the poisonous butterflies.
John Glendinning and Lincoln Brower of the University of Florida studied the mouse, Peromyscus melanotis. They found that in winter it migrates to the mountainsides in central Mexico where monarchs flock in enormous numbers at the same time. The mice then dine on the butterflies, which are nutritious because they are rich in substances known as lipids (Journal of Animal Ecology, vol 59, p 1091).
http://www.newscientist.com/article/mg12817443.100-science-of-mice-and-monarch-butterflies-.html
Can the common house mouse (Mus musculus) tolerate the monarch's cardiac glycosides? I wish I had Athens access. This paper looks like it might shed some light on the subject:
ROTHSCHILD, M. and KELLETT, D. N. (1972), Reactions of various predators to insects storing heart poisons (cardiac glycosides) in their tissues. Journal of Entomology Series A, General Entomology, 46: 103–110. doi: 10.1111/j.1365-3032.1972.tb00115.x
Notes are given of experiments in which mammals and birds were fed with insects which sequester and store cardiac glycosides, and the insensitivity of the quail (Coturnix japonicus Tern.) to these substances is recorded. The variation in predators' reactions to toxic insects is discussed.
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3032.1972.tb00115.x/abstract
A few years ago, just on dusk, I saw a Shining Cuckoo taking the caterpillars off a Swan Plant. It was jumping/flying up from the ground and pecking them off and eating them. It got a hurry up from me - that's for sure. I then covered the plant with shade cloth.
Last night when the wind was starting to get strong and gusty I began to worry about my 3 J's hanging on the Puriri tree outside. I only found 2 still hanging and upon searching for the third one on the ground below, thinking it might have been blown off the tree, I found the caterpillar half eaten on the ground and a weta nearby. Is this another predator to add to the list??
Most weta are omnivores, and will prey on other invertebrates. Since they don't have a backbone or heart they would not be poisoned by the monarch's cardiac glycosides, just as mantids and wasps are not.
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