Here are some observations I have made that need further investigation.
A. Oecanthus pini nymphs raised indoors were observed nibbling on plastic caps used to hold cricket food. Those nymphs did not thrive indoors and were released. The only other species I witnessed nibbling on the plastic caps was an Oecanthus exclamationis nymph. He did achieve adult stage, but consumed more vegetation and cricket food than the O. pini nymphs. It should be noted that the O. exclamationis was found as a 2nd instar on a White pine tree.
Certain juvenile insect hormones are necessary for instar molting. An article at this link (Scientists Use Pine Sap to Create Biodegradable, Renewable Plastics « Inhabitat – Green Design, Innovation, Architecture, Green Building) discusses using conifer sap to create plastic. Another article discussing pine sap and plastics can be found at this link “Antimicrobial Biomaterials and Sustainable Polymers from Renewable Bio” by Mitra Shiran Ganewatta (sc.edu). Perhaps the plastic caps contained a compound which the tree crickets mistook for pine sap?
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B. Placement of oviposited eggs in stems. A census of direction of oviposition marks on 55 different stems in a one acre area in SE Wisconsin was taken. There were 13 different types of plants with oviposition marks. The majority of the holes were drilled on the south, east or west side of the stems. Is this because the ‘sunny’ sides of the stems are warmer and more easily drilled…or is this because the embryos will somehow benefit from the warm of the sun?
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C. Oethecoctonus oecanthi: Multiple fully developed but dead wasps were found inside Oecanthus forbesi egg cases which should have hatched from the stems months before they were manually opened – 12 months after being oviposited by female tree crickets. The reason the wasps had not emerged is unknown. Additionally, occasional copper tinted empty egg cases were found inside stems along with other normally colorless/whitish eggs/cases of successfully emerged tree cricket nymphs. Several of these cases also had fully developed wasps partially in or near them. https://bugguide.net/node/view/1326758/bgimage
How are the eggs of these wasps inserted into the tree cricket eggs? Are they inserted into the eggs after they are oviposited by the tree cricket? The heads of tree cricket eggs are generally situated 5mm from the surface of the stem. Oethecoctonus oecanthi are 3-4mm in length. The ovipositor of Oethecoctonus oecanthi females would have to be longer than their entire length.
If the Oethecoctonus oecanthi eggs are inserted into the tree cricket eggs before they are oviposited by the female tree cricket, when would the transfer take place? These questions need to be investigated by a person with expertise in identifying this species of wasp, and by someone with excellent eyesight as the wasps are very small.