Phylogenetic Overdispersion in Lepidoptera Communities of Amazonian White-Sand Forests
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BIOTROPICA 48(1): 101–109 2016 10.1111/btp.12294 Phylogenetic Overdispersion in Lepidoptera Communities of Amazonian White-sand Forests Greg P.A. Lamarre1,2,3,6, Diego Salazar Amoretti4, Christopher Baraloto2,5,Fred eric Ben eluz 3, Italo Mesones4, and Paul V.A. Fine4 1 Universite Antilles-Guyane, UMR Ecologie des Forets^ de Guyane, Campus agronomique de Kourou, 97310 Kourou, French Guiana 2 INRA, UMR Ecologie des Forets^ de Guyane, Campus agronomique de Kourou, 97310 Kourou, French Guiana 3 Societ e Entomologique Antilles-Guyane (SEAG), 18 lot Amaryllis, 97354 Remire-Montjoly, French Guiana 4 Department of Integrative Biology, University of California, 1005 Valley Life Sciences Building #3140, Berkeley, CA 94720, U.S.A. 5 Department of Biological Sciences, International Center for Tropical Botany, Florida International University, Miami, FL 33199, U.S.A. ABSTRACT In the Amazon basin and the Guiana Shield, white-sand (WS) forests are recognized as a low-resource habitat often composed by a dis- tinct flora with many edaphic endemic plants. Small patches of nutrient-poor white-sand forests can pose a series of challenges to plants and animals. For plants, these challenges have been shown to function as strong filters that in turn drive taxonomic, functional and phy- logenetic plant composition. However, very little is known about animal communities in WS forest and the effect that low-resource availability may have on higher trophic levels. Here, we investigate the diversity of both taxonomic and phylogenetic diversity of three Lepidoptera families’ (Nymphalidae, Saturniidae, and Sphingidae) assemblages between low-resource (White-Sand Forest) and two adja- cent high-resource habitats, terra firme clay and seasonally flooded forests. We found no clear effect of habitat type on taxonomic compo- sition although butterfly and moth species abundance differed among the three contrasted habitats. The WS forest Lepidoptera community is significantly more phylogenetically overdispersed than expected by chance. We suggest that these low-resource habitats fil- ter the number of plant lineages which, in turn, creates a bottom-up control structuring Lepidoptera phylogenetic structure. We recom- mend long-term sampling on Lepidoptera community both at larval and adult stages that may complement this study and test hypotheses linking herbivore phylogenetic structure to plant resource availability and trophic cascade theory. Key words: Amazon basin; bottom-up; Lepidoptera composition; moth, Nymphalidae; phylogenetic structure; varillales. IN THE AMAZON BASIN AND IN THE GUIANA SHIELD, WHITE-SAND caused by environmental filtering. However, very little is known FORESTS ARE RECOGNIZED AS A LOW-RESOURCE HABITAT COMPOSED about the community assembly of animal communities inhabiting BY A DISTINCT FLORA WITH MANY EDAPHIC ENDEMIC PLANTS (Spruce WS forest (but see Saaksjarvi et al. 2006, Alvarez Alonso et al. 1908, Anderson 1981, Fine & Baraloto 2016). Nutrient-poor 2013) and the possible effect that low-resource availability has on white-sand (hereafter WS) forests pose a series of physiological higher trophic levels. challenges to organisms. For plants, these challenges have been For insect herbivores, the resource limitations present in WS shown to function as strong filters that in turn drive taxonomic, could play a significant role on structuring herbivore community functional, and phylogenetic plant composition (Fine et al. 2010, composition, either directly or indirectly. Given that insect herbi- Fine & Kembel 2011, De Oliveira et al. 2014, Fortunel et al. vores have been shown to feed non-randomly and often on phy- 2014). For example, environmental filters have been shown to logenetically related sets of host plant species (Novotny et al. select for plant species with resource conservation strategies in 2002, Ødegaard et al. 2005), one would expected that plant spe- WS forest — i.e., long leaf life span, denser and thicker leaves- cies composition should affect the taxonomic and phylogenetic (Fortunel et al. 2014) in addition to lower leaf production rates structure of herbivore communities. For example, if herbivores than high-resource habitats (Lamarre et al. 2014). The phyloge- are specialists restricted to a subset of phylogenetically closely netic structure of plant communities is also affected by the low- related host plants, then the phylogenetic community structure of resource availability of the WS habitat in the Amazon basin (Fine herbivores may mirror the phylogenetic community structure of & Kembel 2011, Guevara et al. 2016). Fine and Kembel (2011) plants. On the other hand, if herbivores in a community are lar- found overdispersed phylogenetic structure of tree communities gely generalists with regard to host plants, then the phylogenetic in Peruvian WS, and reasoned that if traits that promote habitat community structure of plants will not influence the herbivore specialization are convergent, this overdispersed pattern could be community structure. Several studies have repeatedly shown direct effects of plant species composition on herbivores and Received 26 November 2014; revision accepted 8 September 2015. other higher trophic levels (Blake et al. 2003, Schaffers et al. 6Corresponding author; e-mail: [email protected] 2008, see Lewinsohn et al. 2005 for a review). Moreover, plant ª 2016 The Association for Tropical Biology and Conservation 101 102 Lamarre, Amoretti, Baraloto, Ben eluz, Mesones, and Fine phylogenetic diversity has been shown to correlate with the struc- drier periods in each region. We collected specimens with aerial ture and the composition of herbivore community (Pellissier et al. fruit traps (FT) for butterflies and automatic light traps (ALT) 2013) and/or higher trophic classes (Dinnage et al. 2012). These for moths. The FT consisted of four bait traps installed in the results are also consistent with the idea of a strong bottom-up mid-understory (between 2 to 5 m). A fermented mixture of control of herbivores mediated by plant phylogenetic diversity sugar, rum, and banana juice was placed onto a platform (Schuldt et al. 2014). (40 cm 9 40 cm) into the device, surrounded by a mosquito net Here, we explore the effect that a low-resource habitat has cylinder (100 cm high, 30 cm diam.). For moth collections, we on the community composition of three Lepidoptera families installed a portable automatic light trap (ALT) with an 8-W back- including butterflies (Nymphalidae) and moths (Saturniidae and light tube to collect all arthropods during each new moon of the Sphingidae) that are often dominant herbivores found in both study period (Æ2 d). We installed ALTs in the middle of each tropical and temperate ecosystems. To test the relationship plot and performed a total of 24 sampling-nights. A weak source between habitat type and community composition, we compared of light such as used for ALTs does not attract insects from long taxonomic and phylogenetic diversity of assemblages between distances, resulting in samples that are highly representative of low-resource (WS) and two adjacent high-resource habitats, terra the local habitat and vegetation (Merckx & Slade 2014). Within firme clay (hereafter TF) and seasonally flooded forests (SF) in the studied plots each trap was separated by at least 20 m avoid- Peru and French Guiana. In particular, we address the following ing spatial interferences between and within type of traps. We questions: (1) are WS forest Lepidopteran communities taxonom- employed equal sampling effort in terms of number of day–night ically distinct from adjacent habitats? (2) How are WS Lepi- periods for each trap in each plot and in each country. All Lepi- dopteran communities structured phylogenetically compared to doptera specimens from ALT and FT were sorted, counted, and high-resource forest habitats? The answers to these questions then identified at species level. Unidentified morphospecies are contribute to the understanding of the mechanisms underlying included in the analyses and are still pending identification. community assembly of both herbivore and plants in megadiverse Amazonian forests. SPECIES ASSEMBLY ANALYSES.—First we investigated whether the WS forest Lepidoptera community supports a unique taxonomic MATERIALS AND METHODS composition compared to adjacent SF and TF. First, species rich- ness per each family was plotted among forest habitats using STUDY SITES.—Lepidopteran communities from White-sand (WS), Venn diagrams and the differences in number of species and spe- seasonally flooded (SF) and terra firme (TF) clay forest habitats cies abundance among habitats was tested with chi-squared con- were sampled in four sites in Loreto, Peru and two sites in tingency table tests. In addition, we performed an index of French Guiana. Within a plot network of modified-Gentry plots habitat association using the same analyses as a recent study on of 0.5-ha from a previous study, we installed two types of insect tropical arthropods (Wardhaugh et al. 2012). This index of habitat traps (see below) in 12 plots that represent the entire range of association (Sm) assigned species as habitat specialists (Sm > 0.9), variation in climatic, edaphic, and forest structure factors habitat facultative specialists (0.5 < Sm < 0.9), or generalists observed in the larger plot network (Baraloto et al. 2011). Two (0.33 > Sm > 0.5). Second, we compared the relative abundance replicates of each habitat type were sampled in each country rep- of collected Lepidoptera family for each plot. We constructed a resenting