It was a beautiful, hot, Spring morning, and 3 out of shape committed scientists set out to bait and trap beetles in a mountainous and rugged sub-Mediterranean area of Romania. Enthusiastic, we were carrying 50 traps, anxious to see what surprises will wait for us in those 50 cups over the next several weeks. We wanted to survey threatened and endangered longicorn beetles that live in the unique habitats that make up the Iron Gates Natural Park (IGNP) but we would have been excited to find even the most common of them all! This was a brand new territory for us and one that has never been systematically surveyed. We were looking for one beetle in particular, the endangered European Maple Longicorn Beetle (Ropalopus ungaricus), but found more then we ever expected!
The pheromones we are using are generic (many species of longicorn beetle produce the same or very similar pheromones) and we hope that they will attract a variety of beetle species (Hanks and Miller 2013, Wickham 2014). The pheromones and traps will help shed light on the diversity and community of beetle species, which is critical since the deciduous forests in Romania are among the last remaining habitat in the European Union suitable for the survival and persistence of a variety of endangered species and because knowledge about them is relatively scarce. Additionally, the pheromones we are using have yet to be tested in Europe. So, what we find in the trap cups will be a great big surprise (like Christmas morning… but for insect nerds)!
We walked over 3 kilometres setting up traps, up steep mountains and through open fields. The elevation in Eselnita Valley increased from just under 200 meters above sea level to almost 500 meters in less than 1 km! Within this landscape, there is a temperature inversion causing the Beech trees (which prefer a colder climate and usually grow at higher altitudes) to grow near the valley bottom (200-300 meters), where the river maintains a cooler microclimate. The higher we climbed, the warmer it got, the Beech trees disappeared and were replaced by Oak trees. In the open fields (Mala Valley) it is sunny, hot, and full of wildlife, including wild boar, deer, snakes (vipers!), and insects (lots of ticks!).
While setting up our traps in Mala Valley, we just about walked into a barbed wire… and looked like we trespassed on someone’s land! We had to be careful about setting up our traps because we didn’t know if our presence would be welcome, and didn’t know how serious people are about trespassing. Carefully, we proceeded onto the property in hopes that we would be permitted access to continue our work… And we were greeted with kindness! We met an old couple, Ion and Veta Jianu, who not only welcomed us, but they gave us coffee and homemade cheese (which became my staple food for the next several weeks), and also gave us permission to trap beetles on their land. (In fact, Ion greeted me by hand-kissing without making eye contact, which I learned is a traditional way for a gentleman to greet a lady in Eastern Europe!) Throughout the field season, I would continue to meet Ion every day (no hand-kissing since). Ion spoke no English, but he patiently waited while I strung together a few Romanian words (thanks iPhone data and Google translate!), and we made conversation for hours at a time. We chatted about the beetles captured, the trees and plants I came across in the woods, our families, and the weather (always up to date with weather conditions in the area, as well as in the town where my in-laws were babysitting my son, at the other end of the country). I would often bring leaves from trees where I was catching beetles and Ion would teach me the Romanian name of the tree and its traditional use (scythe handle, cane, etc.). …So, as it turned out, on the other side of that barbed wire was a very good friend!
There are many vulnerable, threatened, and poorly understood beetles in the IGNF. (I will post stories about many of them in the future.) However, there is one beetle in particular that we were interested in finding, the endangered European Maple Longicorn Beetle, Ropalopus ungaricus. This beetle has an endangered IUCN status due to severe destruction of mixed forest habitat for intensive agriculture and urbanization, and because of deficient forest management, and most importantly, the abandonment of traditional land uses (fewer people like Ion and Veta). The Maple Longicorn develops in living and dying Maple trees (Acer spp.) with a preference for pollarded or open trees. Pollarding is a form of traditional forest management in Central and Eastern Europe used to produce more branches and foliage for use as animal feed or firewood. Pollarding also has a side effect of increasing the amount of light that enters the tree canopy, as well as its undergrowth, allowing for optimal conditions Maple Longicorn.
Over the next month and a half we checked the traps daily. We wanted to ensure that none of the beetles were harmed… especially the Maple Longicorn beetle. We were worried about them getting harmed because we caught more then just beetles responding to pheromones for romance (a mate), we also caught beetles looking for a meal! We caught hundreds of checker beetles (Clerus mutillarius) daily (about 10-20 per trap)! The Romanian people I spoke to called these beetles ‘gândacul lup’, or wolf beetles, because they’re amazing hunters and eat everything! So, we had to check the traps daily to reduce the number of Longicorn beetles that would have been on the “wolves” menu.
After an entire month and a half of hiking 1.5 kilometers of rugged terrain daily, we decided to wrap up the project and take down the traps. The pheromones were quickly depleting from the heat and we hadn’t caught any new beetles species in a week. And, although we hadn’t found our target beetle, the endangered Maple Longicorn Beetle (Ropalopus ungaricus), we still had plenty of data for a great story! (As it turns out it’s so elusive that even the Grigori Antipa Natural History Museum in Bucharest, RO, does not have one in their vast collections). However, (and quite ironically) on the very last day we captured a similar species of Maple Longicorn beetle (Ropalopus insubricus), a cousin of our target beetle (and featured on the header this post). So, we are getting closer! We will be back in August to scope out better habitat to trap for the elusive Maple Longicorn Beetle.
Overall, we managed to collect 40 different species of Longicorn beetles and of those approximately 10 are rare, vulnerable, and threatened beetles. One species of beetle was unidentified, possibly a new species or invasive species?? Many beetles were captured in specific habitats within our trapping areas or at different times of the day. I will write more detail about the beetles, their identification, habitat, and behaviour in future posts… So, please stay tuned or “follow” this blog.
In the mean time, for more details on the project, please visit my new page “RO Beetle Project“!
Hanks LM and Millar JG (2013) Field bioassays of cerambycid pheromones reveal widespread parsimony of pheromone structures, enhancement by host plant volatiles, and antagonism by components from heterospecifics. Chemoecology 23:21-44.
Wickham JD, Harrison RD, Lu W, Guo Z, Millar J, Hanks LM, and Chen Y (2014) Generic lures attract cerambycid beetles in a tropical montane rain forest in southern China. Journal of Economic Entomology 107(1):259-267.
Featured image: Ropalopus insubricus