Establishment, distribution, and preliminary phenological trends of a new planthopper in the genus Patara (Hemiptera: Derbidae) in South Florida, United States of America

2.1 Initial detection and suction trap sampling

Initial records of the Florida Patara came from the Florida Department of Agriculture and Consumer Services (FDACS), Division of Plant Industry (DPI). In 2012, we began recording specimens of selected fulgoroids, including Patara, from suction traps, which are large machines that sample air continuously for insects (Halbert and Burckhardt 2020). Florida suction traps are installed in Miami (Miami-Dade County), Immokalee (Collier County), Belle Glade (Palm Beach County), and Winter Haven (Polk County). The trap in Belle Glade began operating in August 2019, and traps at the other sites pre-date the initial find of Patara in 2005. A few samples also were hand-collected by DPI and United States Department of Agriculture (USDA) inspectors and sent to the DPI diagnostic laboratory in Gainesville.

In addition to trap sample monitoring, observed specimens were collected at Montgomery Botanical Center and Zoo Miami (Figure 1) by aspiration and transported to the University of Florida Fort Lauderdale Research and Education Center (FLREC) where they were transferred to 95 % ethanol for further processing. All collection locations were mapped using SimpleMappr (Shorthouse 2010).

Figure 1:

Habitat examples where Patara dolos sp. n. has been collected; (A) Montgomery Botanical Center and (B) Zoo Miami in Miami-Dade County, Florida, U.S.A.

2.2 Photography, dissections, and Illustrations

Specimens were measured, photographed, and dissected using a Leica M205 C stereomicroscope. Genitalia were dissected in generic hand sanitizer. The terminalia was pulled off the abdomen using 000 insect pins and photographed. Subsequently, the terminalia was opened on the lateral side to remove the aedeagus for photography. Hand sanitizer was covered with a thin layer of 85 % ethanol to prevent light refraction from causing excessive glare in the imaging process. Dissected structures were stored in 80 % ethanol at FLREC. Images of specimens and all features photographed were generated using the LAS Core Software v4.12. Illustrations were generated using Inkscape v1.2 (inkscape.org/).

2.3 DNA extraction, PCR parameters, and sequence analysis

For the generation of molecular data, the body of an adult male was placed (minus the extracted genitalia) in a 1.5 ml microcentrifuge tube and total DNA was extracted using the DNeasy Blood and Tissue Kit (Qiagen, Germantown, Maryland, USA). Lysis occurred for 24 h then extraction proceeded according to the manufacturer’s instructions. The final eluate was used as a template for the generation of sequence data for the barcoding region (5′ half) of the cytochrome c oxidase subunit I (COI) gene, 18S rRNA gene, and 28S rRNA gene. PCR reactions contained 5× GoTaq Flexi Buffer, 25 mM MgCl₂, 10 mM dNTP’s, 10 mM of each primer, 10 % PVP-40, and 2.5U GoTaq Flexi DNA Polymerase, 2 µl DNA template, and sterile distilled water to a final volume of 25 µL. Thermal cycling conditions were as follows: 2 min initial denaturation at 95 °C, followed by 35 cycles of 30-s denaturation at 95 °C, 30-s annealing, extension at 72 °C, followed by a 5 min extension at 72 °C. Annealing temperatures and extension times for corresponding primers/loci are presented in Table 1. The PCR product was run on a 2 % agarose gel stained with GelRed (Biotium, Fremont, California, USA) and amplicons of the appropriate size were purified using the Exo-SAP-IT^TM PCR Product Cleanup Reagent (ThermoFisher Scientific, Waltham, Massachusetts, USA). The purified PCR product was quantified using a NanoDropLite spectrophotometer (ThermoFisher Scientific, Waltham, Massachusetts, USA) and sent for sequencing at Eurofins Scientific (Louisville, Kentucky, USA). Contiguous files were assembled using DNA Baser (Version 4.36) (Heracle BioSoft SRL, Pitesti, Romania) and aligned using ClustalW as part of the package MEGA7 (Kumar et al. 2016). Maximum likelihood (ML) trees were generated using the Bootstrap method at 1,000 replicates based on the Tamura-Nei model for the COI, 18S, and 28S loci separately as well as one based on concatenated data forming a consensus tree for COI, 18S, and 28S with MEGA7 (Kumar et al. 2016). ML analysis for phylogenies was generated in IQ-TREE (Minh et al. 2020) using a concatenated matrix of COI (5′ half), 18S rRNA, and the D9-D10 expansion region of 28S. The matrix was partitioned (Chernomor et al. 2016) by marker and the best-fit partitioning scheme and model was selected according to the Bayesian information criterion (BIC) score in ModelFinder (Kalyaanamoorthy et al. 2017) implemented in IQ-TREE. Substitution models selected and applied for each partition of the combined data matrix to ML analysis were (1) COI: TIM2+F+R3 and (2) 28+18S: TN+F+I+G4. Clade support was calculated by 1,000 replicates of Shimodaira-Hasegawa approximate likelihood ratio test (SH-aLRT; Guindon et al. 2010; Hoang et al. 2018) in ML analysis. Reliable support values are SH-aLRT ≥80 and UFboot ≥95 (Guindon et al. 2010; Minh et al. 2013). The resulting trees were viewed on FigTree v1.4.

2.4 Taxon sampling

Taxon sampling for molecular comparison included Patara cooki Bahder & Bartlett and P. vanduzei Ball, for in-group (Patara) comparisons. Out-group taxa (Otiocerinae other than Patara) included: Anotia cerebro Bahder & Bartlett, Anotia firebugia Bahder & Bartlett, Cobacella palmensis Bahder & Bartlett, Sayiana sayi (Ball), Shellenius ballii (McAtee), Shellenius schellenbergii (Kirby), Shellenius serratus Bahder & Bartlett (all Otiocerinae: Otiocerini), Mula resonans Ball, and Sikaiana harti (Metcalf) (Otiocerinae: Sikaianini). Finally, Agoo xavieri Bahder & Bartlett (Derbinae: Cenchreini) was used to root the generated phylogenies. Accession numbers for all loci for each taxon used to construct phylogenies are presented in Table 2. All taxa sequence data was generated from previous studies and deposited in GenBank.

Specimen deposition was at the following locations: University of Florida Fort Lauderdale Research and Education Center (FLREC), Davie, Florida; Florida State Collection of Arthropods (FSCA), Gainesville, Florida; United States National Museum (USNM), Washington D.C.; and University of Delaware Reference Collection (UDRC), Newark, Delaware. Quotation marks (“/”) indicated the label information. Slash marks (/) indicated new line on a label and a double slash (//) indicated a new label.

3.1 Diagnosis

Small, pale species with irregular fuscous markings on forewings. Second antennal segment generally fuscous with pale band extending from apex to about midpoint on posterior and anterior margin. Gonostyli club-shaped with large bifid dorsal process. Aedeagus with three processes, two large arising on right lateral side and a large, upcurved process arising at midpoint. Endosoma complex with six processes arranged in unique orientation.

3.2 Male [3.24–3.27 mm with wings; Table 3]

3.2.1 Color

General body color pale to ivory, abdomen red-orange with fuscous wash (Figure 2); fuscous band on genae at ventral margin of eyes, fuscous patch at laterodorsal margin of clypeus, and second antennal segment fuscous with pale band extending from arista and terminating approximately 2/3 length from apex (Figure 3C); forewings translucent, veins white, majority of irregular fuscous mottling distributed over alar region, red spots along margins (three near apical branches of anterior radial vein (RA), three near apical branches of medial posterior vein (MP), absent at apical margin (Figure 4).

Figure 2:

Adult male habitus of Patara dolos sp. n.; (A) lateral view and (B) dorsal view; scale bar = 1 mm, specimen from Miami-Dade County, Florida, USA.

Figure 3:

Adult male of Patara dolos sp. n.; (A) head, pronotum and mesonotum dorsal view, (B) head, pronotum and mesonotum lateral view and (C) head frontal view; scale bar = 1 mm, specimen from Miami-Dade County, Florida, USA.

Figure 4:

Adult male wing of Patara dolos sp. n.; black text = veins, italic text = crossvein, and green text = cell. Specimen from Miami-Dade County, Florida, USA.

3.2.4 Male terminalia

Pygofer in lateral view very narrow, irregularly sinuate on anterior and posterior margin; narrowest dorsally, widest at basal margin; in ventral view, margin linear, medioventral process absent (Figure 5A and B). Gonostyli in lateral view club-like, narrowest basally, distally expanded to broadly rounded apex, dorsal margin bearing large bifid dorsal process just after midlength, with proximal projection a short, curved hook and distal projection irregularly sinuate, truncate at apex with anterior angle pointed cephalad and posterior angle positioned laterally (Figure 5A); in ventral view, spoon-like, narrowest basally, inner margin expanding at midpoint, widest approximately at 2/3 length, constricting slightly before apex, outer margin curved, lightly sinuate at base; apex appearing medially sub-acute in ventral view and rounded in posterior view (Figure 5B).

Figure 5:

Adult male terminalia of Patara dolos sp. n.; (A) lateral view, (B) ventral view and (C) dorsal view. Specimen from Miami-Dade County, Florida, USA.

Anal tube in lateral view short and thick, not reaching apex of gonostyli, dorsal and ventral margins irregularly sinuate, in dorsal view, roughly quadrate, posterior margin strongly sinuate (Figure 5).

Aedeagus short, straight and club-like, bearing three processes and a short endosoma bearing six processes; two large sclerotized subapical processes arise on right lateral side of aedeagus, with first process (A1) angled laterodorsad, sinuate, second process (A2) curved, approximately twice as long as A1, angled cephalodorsad; third process (A3) arising apically, elongate, angled cephalodorsad initially, strongly angled dorsad at midpoint, nearly reaching base of aedeagus (Figure 6); endosoma with six sclerotized processes, first process (E1) arising along ventral margin of left lateral side, wide at base, narrowing to hooked, sclerotized process at apex, curving along lateral margin to dorsal margin, angled dorsad, second process (E2) small, sclerotized point arising near midpoint on dorsal margin, angled dorsad, third process (E3) arising on right lateral side, angled cephalodorsad, fourth process (E4) arising at same point as E3, curving across midpoint, reaching left lateral side, fifth and sixth processes arising along ventral margin, angled cephalad, E5 situated subapically, E6 arising further cephalad (Figure 6).

Figure 6:

Aedeagus of Patara dolos sp. n.; (A) left lateral view, (B) right lateral view, (C) dorsal view and (D) ventral view. Specimen from Miami-Dade County, Florida, USA.

3.3 Type material

HOLOTYPE: “U.S.A., Miami-Dade Co., Miami / Zoo Miami, 15-X-2023 / Host: Livistona chinensis / Coll.: BWBahder / P. dolos ♂ Holotype”. Holotype is stored in 95% ethanol at FSCA.

PARATYPES: Six males listed below. All specimens stored in 95% ethanol at FLREC except the specimen from the Fruit and Spice Park in Miami-Dade County and Puerto Rico. These specimens are pinned and housed at FSCA and FLREC, respectively.

“FLORIDA: Collier Co., / Immokalee, SW FL REC / 12/XII/2022 / 20/XII/2022 / Coll.: Susan Halbert / Suction Trap – Short/F11”

“FLORIDA: Collier Co., / Immokalee, SW FL REC / 2/X/2023 / 4/X/2022 / Coll.: Susan Halbert / Suction Trap – Short/F11”

“FLORIDA: Dade Co., / Kendall, Old Cutler Rd / 10/III/2023 21/III/2023 / Suction Trap / Col: Susan Halbert”

“FLORIDA: Dade Co., / Kendall, Old Cutler Rd / 27/II/2023 10/III/2023 / Suction Trap / Col: Susan Halbert”

“FLORIDA: Dade Co., Fruit & Spice Park, 12-V-2005, Hand catch, Coll.: Susan Halbert, David Ziesk, Ed Putland, E2005-2471-202”

PUERTO RICO: “Barceloneta / P.R. 22-III-1922 / Mills+Andr. [Anderson] // #2070, / On Mamey [presumably Pouteria sapota (Jacq.) H. E. Moore & Stearn (Sapotaceae)] // UDCC_TCN 00103374” (Figure 7)

Figure 7:

Patara dolos sp. n. from Puerto Rico; (A) habitus lateral view, (B) habitus dorsal view, (C) label, (D) head frontal view, (E) terminalia dorsal view, (F) terminalia ventral view, (G) terminalia left lateral view and (H) terminalia right lateral view.

3.3.2 Patara guttata

ST. VINCENT: “Winward side / St. Vincent, W.I / H.H. Smith / 190. // Patara guttata / Uhler Westw. // UDCC_TCN 00103501” (2 males) (Figure 8) (specimens held at USNM).

Figure 8:

Patara guttata from St. Vincent in Fennah (1952): (A) habitus dorsal view and (B) associated labels.

3.4 Etymology

The Greek term ‘dolos’ refers to the deceptive history of identification of this species.

3.5 Sequence data

For P. dolos sp. n., sequence data was generated successfully for the 5′ region of the COI gene, 18S rRNA gene and D9–D10 expansion region of the 28S rRNA gene. Accession numbers for the corresponding regions sequenced and deposited in GenBank are presented in Table 2. Independent phylogenies for the three analyzed loci showed weak to moderate bootstrap support (60) for P. dolos sp. n. resolving in Patara for COI but very strong bootstrap support for the placement of P. dolos sp. n. in Patara based on 18S (99) and 28S (100) (Figure 9). Furthermore, the tree generated based on concatenated data for all three loci also demonstrated very strong bootstrap support (100) for placement of P. dolos sp. n. in the genus Patara (Figure 10).

Figure 9:

Maximum likelihood phylogenetic trees based on 1,000 replicates supporting the placement of Patara dolos sp. n. within the genus Patara: (A) COI gene, (B) 18S rRNA gene and (C) 28S gene; scale bar = percent nucleotide difference.

Figure 10:

Maximum likelihood phylogenetic tree (−ln L −12,700.4095) based on concatenated data for all loci selected in this study supporting the placement of Patara dolos sp. n. within the genus Patara; scale bar = percent nucleotide variability.

3.6 Remarks

Patara dolos sp. n. can be separated from the other species of Patara by details of the shape and armature of the aedeagus which is illustrated for 12 of the Caribbean species. In P. dolos sp. n. there is a set of large asymmetrical processes (A1 and A2) on the right lateral side. These structures are present in Patara inermis (Fennah), P. cooki, and P. mimula (Fennah) however they are significantly smaller in these species. Notably, P. guttata lacks these processes on the right lateral side. In addition to lacking the A1 and A2 processes observed in P. dolos sp. n., P. guttata also lacks various endosomal processes present in P. dolos sp. n., namely E1, E3 and E5. Biometric data for P. dolos sp. n. are presented in Table 3.

The armature of the aedeagus of P. dolos sp. n. from Florida matches that of the specimens that Caldwell and Martorell (1951) reported from Puerto Rico (Figure 7) as P. albida. We consider these to be conspecific.

3.7 Phenology, distribution and host range

The first specimens of P. dolos sp. n. were collected by hand in 2005. In 2012 we began recording various fulgoroids collected in the trap, beginning with the last few samples of 2011. One of these included P. dolos. sp. n. For the first few years, trap captures were few, but there was a noticeable increase in late 2015 (Figure 10). Based on suction trap data, from 2011 to 2021, no specimens were collected in May. The population begins to increase in the summer, generally peaks in September, and then begins to decrease slowly through the fall, winter, and spring (Figure 11).

Figure 11:

Total (blue) and average (orange) number of adults of Patara dolos sp. n. collected each month from 2011 to 2021 (A) and total number collected annually from 2011 to 2021 (B) from a suction trap at the United States Department of Agriculture facility in Coral Gables, Florida, USA.

Hand collecting and suction trap data of P. dolos sp. n. have been restricted to various locations throughout Miami-Dade County with a few hand collecting records from Broward County (two specimens in Davie and one specimen in Coral Springs) (Figure 12). One specimen was collected from the suction trap in Collier County (Immokalee) in July 2019 (Figure 12).

Figure 12:

Distribution of Patara dolos sp. n. in Florida based on suction trap data and records from hand collecting by sweep net.

Thus far, hand collecting of P. dolos sp. n. has occurred mostly on palms (with the exception of early records, having been collected on canistel), however this might be due to biased sampling. Specimens were collected from Arecaceae: Elaeis oleifera Kunth, Livistona chinensis Jacquin, Sabal palmetto Walter, S. romanzoffiana, Verschaffeltia splendida Wendl, and W. robusta. Puerto Rican specimens were collected on Sapotaceae, citrus, and Annona (Annonaceae).

3.8 Discussion

The documentation of another new species of planthopper on palms is valuable for advancing the understanding of the evolutionary relationship between derbids and palms. Survey work in Barbuda identified a new species of Patara (P. cooki) on coconut palms in an abandoned plot that was largely a monoculture and it was found in high abundance on coconut frons but absent on all other vegetation, indicating it fed exclusively on coconut palms (at least in that habitat) (Bahder et al. 2021). Many of the Patara in the Caribbean are generally superficially very similar and are likely closely related. While the phylogeny in this study is preliminary and supports placement of the novel taxon in Patara, it does show strong resolution of P. dolos sp. n. adjacent to P. cooki. As more taxa become available from the region, it is likely that these pale form, Caribbean Patara will likely form a strongly supported, monophyletic clade. Because of this, it is also likely that other similar species are likely also palm specialists. Survey work in Costa Rica and Colombia (Bahder, unpublished data) also have resulted in the discovery of undescribed species of Patara, some of which are similar in appearance to the Caribbean species observed so far. In both countries, these species of Patara were collected from oil palms (Colombia) or native palms in natural ecosystems and never were collected on surrounding vegetation.

The new species described herein is of particular interest because it is a recently established species in Florida, where invasive species are a common occurrence. While this species is likely not of economic importance, documenting its establishment and biology in Florida is important for further understanding host relationships (mentioned above) but having these published records helps highlight the larger issue of common invasion events in the state and helps support the justification and need for continued monitoring. The exact time of introduction is unknown but due to the first detection in 2005 and subsequent increase in population from 2011 to 2021 as well as the absence of the species in historical collections from Florida in the FSCA, we consider that this is an adventive species to Florida. It is important to note that the phenology data presented is based on a trap at a single location. Future efforts need to standardize trapping at multiple locations where specimens have been collected to ensure the seasonal trends observed in this study are consistent. However, due to the very limited range of this species, the trends observed based on the trap data presented are likely to be consistent with other locations where P. dolos sp. n. has been collected. Because of this, the trend of more adults being found in fall and winter months is preliminary and future efforts to establish long term trends as the species adapts to Florida climatic conditions are necessary. Based on population and distribution, it appears that P. dolos sp. n. first appeared along the coastal region of Miami-Dade County and is spreading slowly and increasing in population in southern Florida. In this instance, the morphological match to historical specimens of Patara from Puerto Rico indicate that Puerto Rico is most likely the geographical origin of this species. The pathway by which P. dolos sp. n. became established in Florida is not known, however, it could have been the result of infested, imported plant material (human mediated) or natural dispersal via vegetation or debris that could be exacerbated by hurricanes or strong weather patterns. To date, P. dolos sp. n. has been found primarily on palms.

Current survey efforts of planthoppers in the Caribbean have focused on palms due to a renewed interest in the vector relationship between planthoppers and palm-infecting phytoplasmas, a result of the establishment of lethal bronzing in Florida (Harrison et al. 2008). Recently, the cixiid planthopper Haplaxius crudus Van Duzee (Hemiptera: Cixiidae) was determined to be the vector of lethal bronzing in Florida (Mou et al. 2022). These findings have led to speculation that other, closely related species of planthoppers might be competent vectors of palm phytoplasmas in other regions of the Caribbean where these phytoplasmas are endemic but H. crudus is rare or missing. These survey efforts have yielded many new species of both cixiids and derbids. Some species, such as Oecleus mackaspringi Bahder & Bartlett (Hemiptera: Cixiidae), a somewhat close relative of H. crudus that occupies a similar niche, are considered putative vectors of lethal yellowing (Myrie et al. 2019). The role derbids play in the transmission of phytoplasmas in palms has not been established.

Very few derbids are considered pests or are of economic importance. Proutista moesta (Westwood) (Hemiptera: Derbidae) has been associated by molecular testing with Kerala wilt disease of palms in India (Edwin and Mohankumar 2007), but transmission was not confirmed. While P. dolos sp. n. is likely an innocuous species, the discovery of this species further highlights the need for continued monitoring because other groups of planthoppers that can serve as vectors of pathogens could follow similar pathways.