Mediterranean Katydid Food Experimentation

Now that we have obtained a stable culture of Mediterranean Katydids (Phaneroptera nana) we decided to do some experimenting with them, similar to what we have done with our Mexican Bush Katydids (Scudderia mexicana). We tried feeding them with various foods such as flower pollen, honey, and dead fruit flies! 

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Because most Orthoptera are generally flexible with host plants unlike many members of Lepidoptera, and since most "herbivorous" katydids are actually omnivorous (some katydids are actually strictly carnivorous too) we decided to do some experimenting with our thirteen newly collected P. nana specimen. We have also conducted food experimentation on the native Mexican Bush Katydid so we decided to give it a shot and see whether the two species have similar preferences!

Our first test was to see whether P. nana would readily accept apple (Malus domestica) or plum (Prunus spp.) leaves since this is what we primarily feed our S. mexicana. When we left the leaves in our P. nana enclosure overnight, there seemed to be little feeding activity on the leaves, but the katydids did accept the flowers we offered them -- Purple Morning Glory (Ipomoea purpurea) and pink Rose (Rosa spp). Not too surprising since we found most of them on a Purple Morning Glory vine, but it was definitely something worth noting. 

After this, we performed a series of basic food tests out of curiosity. 
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1. Pollen, Pine (Asian Pinus spp.) and Blue Hibiscus (Alyogyne huegelii?)​​​         

Because pollen is extremely nutrient dense due to the fact that most plants expend a considerable amount of resources towards reproduction, it is rich in many nutrients and is about 40% protein. We tried feeding some nymphs pine pollen that we ordered online (sourced from Asia) that was removed from the flower and with the cell-walls cracked. While they did not eat the pine pollen on their own accord, they did not refuse it when prompted (placed near the mouth using a toothpick, but not forcibly fed). On the other hand, whole pollen grains still attached to freshly picked Blue Hibiscus flowers were completely eaten after being placed in the enclosure for a day. We also observed pollen eating from various flowers including Blue Hibiscus by S. mexicana, so we concluded that they do like it and it would be a good idea to use flowers with high pollen content. Needless to say, it wouldn't hurt because katydids probably encounter plenty of pollen in the wild. ​

2. Honey, harvested from Manuka trees (Leptospermum scoparium)
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Honey is essentially nectar (and a substantial amount of pollen) that has been processed through the bee's digestive system where it is modified by enzymes. It is comprised primarily of the fruit sugars -- glucose, fructose, and sucrose -- that may or may not be appealing to katydids. In any case, we used a toothpick to prompt our P. nana nymphs to feed on a high quality (10+) store-bought Manuka honey. We also tried to stick the honey to their bodies since they habitually clean themselves with their mouthparts and would likely eat it if we put it there. But similar to the pollen test, they did not seem to actively enjoy being fed from a toothpick though they readily accepted it.

3. Dead Fruit Flies (Drosophila hydei​)
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We culture D. hydei fruit flies for feeding our European Mantis (Mantis religiosa). We found previously that S. mexicana really has an appetite for freshly killed fruit flies and seemed quite clearly omnivorous in nature. When we tried to feed fruit flies to P. nana, they did seem to have an affinity for it and would willingly eat it on their own accord if dead flies were left in the enclosure. However, we didn't see them gobble them up like our S. mexicana does, but perhaps it was because our P. nana were much smaller in size. At the same time, we noted a critical difference between the head sizes between the two species. P. nana's head is proportionally much smaller compared to the body compared to S. mexicana and therefore has smaller and less powerful food-tearing mandibles (also supported by the fact that they prefer softer flower petals over leaves). We think that P. nana is probably not carnivorous in nature. ​​

- Brian