When it comes to insects many people often inadvertently recoil away in disgust or terror, thinking only of their legs as creepy or their eyes as beady. But what not many people realise is that insects perform many important roles not only in regards to natural ecosystems but also to our society as a whole. Thinking of only beetles we can recognize their roles in soil bioturbation and nutrient cycling, decomposition which is beneficial to new growth, and most importantly, pollination, something society’s food production couldn’t function without (Costanza et al. 1997). Furthering this point
Figure 1: Arctia villica
and moving away from ecological values, many of our beloved creepy crawlies have economic benefits as well, such as the production of honey and wax from bees or the creation of silk from the silkworm (Akre et al., 1991). If that isn’t enough to convince you then consider the natural biological pest control some species can provide. When assessed in the 1990’s it was found that insects were mostly responsible for saving us $400billion in natural biological control (Saul, 1999), just imagine the mosquitoes and flies we’d be facing without their help.
Now that the importance of these often overlooked creatures is understood we can justify why it is so important to invest in scientific research and conservation efforts towards them. However, since approximately 80% of all animal species on earth are insects this task can seem rather daunting (Saul, 1999). So much so that there is a distinct lack of information surrounding not only the behaviour of insects but more shockingly the identification of species themselves (Purdue University, 2014). At Archipelagos, we are attempting to fill this information gap by identifying what insect species can be found on Samos. Therefore we are providing a baseline for further studies into the conservation needs, behaviours, and ecological importance of the species found.
Figure 2: Basic set up of a pitfall trap.
In order to undertake this study, 3 methods were used. The first is pitfall trapping, which involves placing containers at level with the ground with a cover above it propped up by rocks, allowing crawling insects to fall in but making it difficult for them to fly out again (Figure 2).
The insects are then either collected or photographed to be identified back at the base. Method 2 involves the use of a light trap. This involves placing a light in front of a white sheet, which inevitably attracts nocturnal flying insects such as moths and butterflies (Figure 3). Once on the sheet, they are again photographed or taken in jars for identification. Finally, the last method involved no trapping but simply walking a line transects of approximately 20 metres and taking photos and notes of any insects seen off the transect at no further than 5 metres. All of these methods combined ensured a variety of habitats were covered, therefore allowing for a larger range of insect diversity.
Figure 3: Light Trap Set Up
Once identified the insects were then placed into various identification sheets based on their grouping (i.e. butterflies, beetles, etc.). In order to help future studies the sheets contained a brief description and photos of the insect for ease of ID, where it can be found on the island, it’s conservation status and what habitats it prefers.
At the end of the 3 months, 76 species were identified with the major groups being Odonata (Dragonflies and Damselflies), Lepidoptera (Butterflies and Moths) and Coleoptera (Beetles). As seen in Figure 4, Odonata were the largest group found at 35 species as there is an abundance of wetland habitats on Samos Island; this groups preferred habitat.
Figure 4: Number of Species Identified in Each Major Group
From this study there were also some interesting finds that could lead onto further research. For instance, the Southern Hawker (Aeshna cyanea, Figure 5) is not meant to emerge into flight until June however this species was found at the Archipelagos Base in early May (Ferreira, S. & Samraoui, B. 2010). Which may indicate some sort of change in the environment causing their flight period to become earlier.
Figure 5: Aeshna cyanea Found at Archipelagos Base
Nicole Tomlinson
BSc Ecology and Conservation Biology, Griffith University
References:
Akre, R.D., Hansen, L.D., & Zack, R.S. 1991, “Insect Jewellery”, American Entomologist, v27, n2
Costanza, R., et al. 1997. “The value of the world’s ecosystem services and natural capital”. Nature 387:253-260.
Ferreira, S. & Samraoui, B. 2010. “Aeshna cyanea”. The IUCN Red List of Threatened Species 2010: e.T165524A6056319. Downloaded on 26 June 2018
Purdue University, (2014). “Who Let the Bugs Out?” [online] Available at: https://extension.entm.purdue.edu/radicalbugs/index.php?page=importance_of_insects [Accessed 26 Jun. 2018].
Saul, L., 1999. “Importance of Insects and Their Arthropod Relatives”, Save Nature.org, file:///C:/Users/Nicol/Downloads/Importance%20of%20Insects.pdf
