Food for thought. Rainforest carrion-feeding butterflies are more sensitive indicators of disturbance history than fruit feeders

Abstract

Tropical forests have, and in many areas continue to experience both severe and subtle forms of human disturbance; most commonly from hunting, logging and clearance for agriculture. The ability to detect a full range of impacts is essential to understanding how biodiversity responds to human disturbance. Since monitoring the entire biodiversity of a tropical forest is an impossible task, specific groups of biodiversity are often used as biological indicators. Due to their relative ease in detection and identification, their sensitivity to environmental change and their short generation time, butterflies are suggested to be one of the most effective biodiversity indicators for tropical forest monitoring. However, most biodiversity monitoring of tropical ecosystems using butterflies relies only on one subgroup, the fruit-feeding butterflies, or Nymphalidae. Here we assess for the first time if the use of carrion-feeding butterfly communities might improve our ability to detect and monitor human impacts and conservation management outcomes in tropical forests. We analysed species richness, abundance and community composition of rainforest fruit and carrion butterfly communities to see how effectively they detect known differences in forest disturbance history, between three different vertical strata of rainforest, and assess whether they provide stable results across different seasons. We found that compared to fruit-feeding butterflies, sampling carrion-feeders detected greater species richness and abundance for the same survey effort, detected more pronounced effects of known differences in historic disturbance, and showed greater temporal stability in biodiversity patterns across the year. We also identify for the first time a series of indicator butterfly species and tribes that could be used as biological indicators to study biodiversity responses to human disturbance and differences across vertical strata of the rainforest. We therefore suggest that carrion-feeding butterfly communities will be a powerful addition to the family of indicators groups that are available for monitoring the impacts of human disturbance on tropical biodiversity.

The effects of insecticides on butterflies – A review

“…Butterflies play an important role in ecosystems as plant pollinators (Feber et al, 1997;Potts et al, 2016) and as prey for other organisms (Strong et al, 2000). Well-known to the general public, they are well monitored, recognised as indicators of environmental health (Whitworth et al, 2018) and as such they have been used to measure impact of factors such as climate change (Schweiger et al, 2012) and landscape fragmentation (Scriven et al, 2017). Comparatively, their ecology and abundance is much better known than any other invertebrate taxa (New, 1997).…”

Effect of Climatic Conditions and Land Cover on Genetic Structure and Diversity of Eunica tatila (Lepidoptera) in the Yucatan Peninsula, Mexico

“…Short lifecycles and variability for their resilience capacities make insects good bio-indicators [5]. Many studies have demonstrated the advantages of Lepidoptera as bio-indicators in tropical [6][7][8][9] or temperate [10,11] ecosystems. For the Yucatan Peninsula, Pozo (2006) [12] endorsed nine butterfly species as environmental indicators of undisturbed tropical forest and seven for disturbed tropical forest.…”

Are We Using the Most Appropriate Methodologies to Assess the Sensitivity of Rainforest Biodiversity to Habitat Disturbance?

“…disturbance on Lepidopteran biodiversity (see Table 1). However, in their comparison of carrion-and fruit-baited traps, Whitworth et al (2018) show that in addition to higher capture rates and attracting a wider array of the community, carrion-baited traps are more sensitive to rainforest disturbance effects and less susceptible to seasonal fluctuations. They therefore suggest that the community attracted to carrion-baited traps performs better as a biodiversity indicator group than the community associated with fruit-baited traps.…”

“…A key part of this involves carefully selecting the most appropriate methods to target these groups. We should further question paradigms that exist for prevailing methods, as Whitworth et al (2018) and others have done (Barlow, Mestre, et al, 2007), and continue to explore how biodiversity within the upper reaches of the rainforest canopy might be differentially impacted to those close to the ground (Nakamura et al, 2017). If we utilize methodologies with precision that accurately assess habitat disturbance, we will enhance our ability to predict how forest ecosystems respond to human disturbances and recovery interventions at multiple scales.…”

“…Yet, how do different methodologies that we use for biodiversity assessments of tropical forests influence the results that we detect and ultimately our interpretations about the value of impacted or recovering landscapes for biodiversity conservation? A recent study by Whitworth, Pillco Huarcaya, Gonzalez Mercado, Braunholtz, and MacLeod (2018) tests the paradigm that fruit-feeding butterflies are the most suitable indicator group of Lepidoptera with which to assess human-mediated rainforest disturbance. Despite previous studies suggesting that baiting traps with carrion results in higher capture rates and displays a greater representation of the overall community (Hamer et al., 2006), it has become the norm for studies in tropical rainforest to use fermented fruit-baited traps to assess the impact of habitat disturbance on Lepidopteran biodiversity (see Table 1).…”