In my last post, I mentioned some of the challenges facing firefly populations around the world, including habitat loss and pollution, and this week I wanted to get a better sense of our options for halting population declines and making a human-dominated landscape more firefly-friendly. To be honest, I was kind of hoping to find a bit more than I found on conservation efforts (when you consider that the first recorded firefly protection plan dates to 1835 in Spain (Pyle 1995), I had assumed that quite a variety of strategies had been tried since then), but at least there are some ideas on where to start and important issues to consider as we move forward.
What are some general strategies to help firefly populations? Certainly, habitat restoration is a good place to start. When abandoned rice paddies in Kanazawa, Japan were restored, Luciola lateralis firefly populations doubled over four years (Koji et al. 2012). Researchers in Malaysia noted that the loss of specific trees along rivers decreased firefly reproductive success and recommended an ecosystem-wide approach to firefly conservation because fireflies depend on so many elements within any habitat (Jusoh et al. 2009/2010). This means looking not just at the presence of specific prey or plant species, but also watershed dynamics, pollution levels, dispersal potential, etc. Dealing with the light pollution issue is also key. As I mentioned before, bright lights inhibit flashing, and a study in Switzerland found that males were not attracted to females positioned under street lights, and females did not actively seek darker areas (Ineicher & Ruttimann 2012), so if the street lights cover the entire area occupied by females, the males will not find them. This suggests two strategies: 1) design street lights so that light is focused onto the hard surfaces, such as streets and parking lots, that they are meant to illuminate and away from vegetative areas utilized by fireflies; and 2) since many species of fireflies have specific times of night when they are most active, consider reducing artificial light during those few hours. The type of light emitted is also important- Hagen & Viviani (2009) found that fireflies in Brazil were sensitive to not only light intensity but also color, so using outside lights which fall within a different range of the spectrum could help alleviate negative impacts on firefly populations. Ecotourism may be a way to preserve firefly habitat in areas with synchronized flashers- interviews with local residents of a firefly gathering area in Thailand found that the level of involvement in firefly conservation was directly related to level of involvement in firefly ecotourism; however, there is a danger of environmental damage when ecotourism activities are highly popular and/or unregulated, and Chaikaew (2005) recommended better communication and education efforts, as well as the development of daytime activities so that local firefly populations are not over-exploited.
What about augmenting firefly populations? So far, although researchers are still learning about this option, there appear to be a few problems. Attempts to rear fireflies in captivity have not met with unqualified success– keeping large numbers of larvae together led to unequal growth in individuals, the spread of disease, and high mortality rates, and, while separating larvae did have greater success (35 of 80 individuals completed their lifecycle), the success rate was still below 50% (Ho et al. 2010) and individual rearing of fireflies may not be feasible on the scale needed to supplement wild populations. And the obstacles to captive breeding and rearing have expanded importance because of our use of luciferase in medical research- wild fireflies are harvested in the US to obtain the chemical. In one county in Tennessee alone, ~40,000 males were harvested in 2008, despite the fact that a synthetic alternative exists, and researchers believe that this level of harvest pressure is unsustainable in the long term (Bauer et al. 2013). Collecting fireflies from healthy wild populations and transferring them to other locations may not work, either. In Japan Luciola cruciata fireflies which had been moved from one location to another to supplement the local population had different flash rates from the local L. cruciata fireflies, and the different in flash patterns may have caused reproductive isolation of the native insects while the introduced insects met with reproductive success (Iguchi 2009). This suggests that adding to local populations may not be the solution it might seem even when the species are the same.
The ideas I discuss above are very much big-picture perspectives; there isn’t a huge amount of detail about the things that we can do as individuals, in our own small spaces, to support fireflies. For my final post of the month, I’ll investigate smaller-scale actions which can add up to big gains for fireflies.
Works cited:
Bauer, CM, Nachman, G, Lewis, SM, Faust, LF, and JM Reed. 2013. Modeling effects of harvest on firefly persistence. Ecological Modelling 256: 43-52.
Chaikaew, P. 2005. Local people participation in firefly ecotourism management: a case study in Ban Samaechai, Petchaburi Province. Master’s thesis, Mahidol University, Thailand: 1-3.
Hagen, O and VR Viviani. 2009. Investigation of the artificial night lighting influence in firefly (Coleoptera: Pampyridae) occurrence in the urban areas of Campinas and Sorocaba municipalities. Anais do IX Congresso de Ecologia do Brasil : 1-2.
Ho, J-Z, Chiang, P-H, Wu, C-H, and P-S Yang. 2010. Lifecycle of the aquatic firefly Luciola ficta (Coleoptera: Lampyridae). Journal of Asia-Pacific Entomology 13: 189-196.
Iguchi, Y. 2009. The ecological impact of an introduced population on a native population in the firefly Luciola cruciata (Coleoptera: Lampyridae). Biodiversity and Conservation 18: 2119-2126.
Ineicher, S and B Ruttimann. 2012. Impact of artificial light on the distribution of the common European glow-worm, Lampyris noctiluca (Coleoptera: Lampyridae). Lampyrid 2.
Jusoh, WFAW, Hashim, NR, and ZZ Ibrahim. 2009/2010. Distribution, abundance and habitat characteristics of congregating fireflies (Luciolinae: Lampyridae) in Rembau-Linggi Estuary, peninsular Malaysia. In Proceedings of Postgraduate Qolloquium Semester 1, Faculty of Environmental Studies, Universiti Putra Malaysia: 331-336.
Koji, S, Nakamura, A, and K Nakamura. 2012. Demography of the Heike firefly Luciola lateralis (Coleoptera: Lampyridae), a representative species of Japan’s traditional agricultural landscape. Journal of Insect Conservation 16: 819-827
Pyle, RM. 1995. A history of Lepidoptera conservation, with special reference to its Remington debt. Journal of the Lepidopterists’ Society 49: 397-411.