Evolution of Paedomorphosis in Coleoptera: Why so many beetles never grow up?

Paedomorphosis is a heterochronic syndrome in which adult individuals display features of their immature forms. In beetles, the paedomorphic syndrome can be expressed as a mosaic of characteristics, which can include the reduction of sclerotization and/or loss of flight ability, miniaturization of morphological structures, the predominance of a K-reproductive strategy and enhanced fecundity of females. In extreme cases, adult paedomorphic beetles can be completely larviform and fully resemble their larval stages. However, despite the conspicuousness of this syndrome in beetles, especially in the superfamily Elateroidea, which includes click-beetles, fireflies and rail-road worms, the processes that generate these modifications and overall effects of paedomorphosis remain largely unknown and poorly studied.

Picture1Diversity of beetles affected by paedomorphosis. A. Berberomeloe aff. majalis (Meloidae), Europa. Ferran Turmo Gort. B. Drilus flavescens (Elateridae) macho (alado) e fêmea (larviforme) in copula. Europa. bobgaia. C. Platerodrilus sp. (Lycidae), female adult, Borneo. Budak. D. Ripiphorus sp. (Coleoptera, Ripiphoridae) male, Canada. Ilona L. E.  Micromalthus debilis (Micromalthidae) adult and larvae, IL, US. Alex Wild. F. Thylodrias contractus (Dermestidae) male (alate) and female (larviforme) in copula, US. Kerry Matz. G. T. contractus, female NY, EUA. Antonio Liberta. H. Photinus brimleyi (Lampyridae), female, TN, EUA. Charley Eiseman. I. Photinus collustrans (Lampyridae), female, FL, EUA. David Almguist.

Despite repeated reports and studies mentioning PDM in beetles none of these investigated in depth the consequences or the potential adaptive value of structures affected by paedomorphic processes. It is currently unknown whether the paedomorphic adaptations in different beetle lineages have the same evolutionary origins (i.e. are homologous) or if they have evolved independently. Current gaps in the state-of-the-art of PDM in beetles can be summarized by:

  • A lack of a synthesis in knowledge of how paedomorphic processes affect beetle evolution
  • A lack of a test of hypothesis of homology for characters highly affected by paedomorphic processes in beetles, resulting in unresolved phylogenies of their lineages that include paedomorphic species (in particular, conflicting tree topologies between morphology and genomic data).
  • A lack of a general hypothesis explaining the adaptive values of the repeatedly evolved paedomorphic traits in beetles that would frame the investigation of their potential biological drivers.

To address to these questions, my research integrates morphology, natural history data and NGS. This is the first  broad-scale case study investigating the manifestation of paedomorphosis in animals using beetles as a model to understand the evolution of convergent paedomorphic phenotypes. More on this soon!

Systematics of the New World Lycidae (Coleoptera, Elateroidea)

Lycidae are one of the most spectacular beetles in the world. Known for their striking colorations and particular involvement in mimicry-ring complexes, aposematism relationships and for being affected by the paedomorphic syndrome. Despite recent advances on higher level phylogenetics of the family, there is still much ground to cover on the taxonomic and biology aspects of this group, in special in the New World region. With the exception of the North America north of Mexico fauna, it is nearly impossible to identify the remaining of the New World Lycidae species, and in many cases even the genera.

As a taxonomist and systematist interested in this group and in the evolution of paedomorphosis in beetles, I strive to overcome those shortcomings in the knowledge of the group through the integrative use of morphology of extant and fossil taxa, natural history data, DNA barcoding and molecular data (Sanger and NGS). My long term goals are to produce multilingual illustrated identification keys to all New World Lycidae species and genera and to revise the genus Calopteron Laporte, one of the most speciose groups in the Americas.

Related publications:

  1. Ferreira, V.S. & Costa, C. 2015. A description of the Larva of Metapteron xanthomelas (Lucas, 1857) from the Restinga Forest of Southeastern Brazil (Coleoptera: Lycidae, Calopterini). Zootaxa, 3915: 295-300.
  2. Ferreira, V. S. 2015. A new species of Acroleptus Bourgeois (Coleoptera: Lycidae) from the Brazilian Amazonian rainforest, with a note on its homonymy with Acroleptus Cabanis (Aves). Zootaxa, 3949: 297-300.
  3. Ferreira, V.S. 2016. A new species of Falsocaenia Pic, 1922 from Amazonian Rainforest (Coleoptera: Lycidae) with an updated key to the species. Zootaxa, 4105: 497-499.
  4. Ferreira, V.S. 2016. A revision of the genus Macrolygistopterus Pic, 1929 (Coleoptera, Lycidae). Zootaxa, 4105: 321-338.
  5. Ferreira, V.S. & Ivie, M.A. 2016 Redescription of Cephalolycus Pic, 1926 (Coleoptera: Elateroidea: Lycidae) and a Discussion on Its Taxonomic Position. The Coleopterists Bulletin, 70(3): 663-666.
  6. Ferreira, V.S., Barclay, M.V.L. and Ivie, M.A. 2018. Redescription of Aporrhipis Pascoe, 1887 (Coleoptera: Lycidae) With a Discussion of its Tribal Placement. The Coleopterists Bulletin, 72(2):371-375.
  7. Ferreira, V.S. and Ivie. 2018. A Revision of Lycinella Gorham, 1884 with the Description of six New Species (Coleoptera, Lycidae, Calopterini). Zookeys 792: 69-89. 
  8. Ferreira, V.S., and Ivie, M.A. 2018. A Review of the Nearctic Genus Lucaina Dugès, 1879 (Coleoptera: Lycidae: Lycinae: Calochromini), with Descriptions of Two New Species. The Coleopterists Bulletin, 72(3):393-406.
  9. Ferreira, V.S. and Silveira, L.F.L. A New Paedomorphic Genus of Net-Winged Beetles from the Atlantic Rainforest (Coleoptera, Elateroidea, Lycidae). Papéis Avulsos de Zoologia. v.60.special-issue: e202060(s.i.).35. 
  10. Ferreira, V.S. 2020. Revision of Acroleptus Bourgeois, 1886 and Descriptions of New Aporrhipis Species (Lycidae, Calopterini, Acroleptina). Journal of Natural History. 53:45-46, 2739-2756.
  11. Ferreira, V.S., and Tettamanzi, L. 2022. Falsoceratoprion fumagalliae new genus and species: The First Calopterini from Dominican Amber (Coleoptera, Lycidae). The Coleopterists Bulletin. 76(2): 288-292.

Ongoing subprojects 

Revision, Phylogeny and Biogeography of Thonalmus Bourgeois

The lycid genus Thonalmus is one of the prettiest lycid beetles in the world, and probably the most studied genus among the Neotropical Lycidae groups. Endemic to the Greater Antilles and Montserrat,  it is the sole genus in its tribe, Thonalmini. With a unique morphology and bright colors, the taxonomy and systematics at species-level is chaotic, and to the moment identification of most species within the genus is impossible. An integrative species level phylogeny, biogeography analyses and identification keys and descriptions and redescriptions of all species of the genus have been produced and the manuscript is in process of submission to a respected journal in the field.

Figure 1

Thonalmus species diversity. A. Thonalmus new sp., Dominican Republic (Photo: Pedro Genaro Rodrigues). B. Thonalmus new sp, Constanza, La Vega, Dominican Republic (Photo: Ruth Bastardo) (CC BY-NC 4.0). C. Thonalmus bicolor, Dominican Republic (Photo: Carlos de Soto Molinari). D. Thonalmus new sp, Cordillera Central, Dominican Republic (Photo: Francisco Alba Suriel). E. Thonalmus hubbardi, Montserrat (Photo: Michael A. Ivie). F. Thonalmus militaris, Jamaica (Photo: Birdernaturalist). G. Thonalmus new sp, National Botanical Garden of Santo Domingo, Dominican Republic (Photo: Francisco Paz). H. Thonalmus aulicus, Caimanera, Cuba (Photo: Wayne Fidler) (CC BY-NC 4.0).

Life Stage Associations, Revision and Systematics of the Extreme Paedomorphic Leptolycini

A male of Leptolycus (Baholycus) sp. (Coleoptera, Lycidae, Leptolycini) from Loma de blanco, Bonao, Republica Dominicana. Image source: Carlos de Soto Molinari.

The Leptolycini are a group of paedomorphic beetles endemic to the West Indies. Members of this group are characterized by possessing adult females that lack the characters that define the adult form of a beetle. These extreme paedomorphic adult females are often termed “larviform” females, and in most cases, the status of a given individual as an adult or larvae is not really known.

Plate. Paedomorphosis

A. A scheme showing the hypothesized evolutionary relationships of Lycidae (modified from Kusy et al. 2019). Red circles indicate groups in which paedomorphosis has developed at least once in the subfamilies. B. Distribution of Lycidae lineages across the different zoogeographical zones. Map of the different ecozones modified from Wikimedia commons. Originally made by carol and used under a CC BY-SA 3.0.

larviform typ2
Adult Leptolycini female? collected in the El Verde Field Station, El Yunque, Puerto Rico.

In contrast, males of these sexually dimorphic species have all the normal adult characters and are immediately identifiable as a beetle. My current research is focused in unraveling the high diversity in this sexually dimorphic case of extreme paedomorphic beetles.

A manuscript containing a review of the Puerto Rican Bank Leptolycini fauna and the first life-stages associations using morphology and DNA barcoding is under review in Insect Systematics and Diversity. A taxonomic revision, association of males/females and a species level phylogeny of the group is currently under development.

Screen Shot 2022-01-21 at 11.35.05

First fossil species of an the extant Leptolycini genus Cessator Kazantsev: Cessator brodzinskyi Ferreira and Ivie, 2017 from Dominican Amber.

Related publications
  1. Ferreira, V.S. & Ivie, M.A. 2017. The First Fossil Species of the Extant Genus Cessator Kazantsev (Coleoptera: Lycidae): A New Leptolycini from Dominican Amber. The Coleopterists Bulletin, 71(1):57-60.
  2. Ferreira, V.S., and Ivie, M.A. 2022. Lessons from a Museum’s Cabinet: DNA barcoding and Collections-based Life Stage Associations Reveals a Hidden Diversity in the Puerto Rican Bank Paedomorphic Lycidae (Coleoptera, Elateroidea). Insect Systematics and Diversity. 6(3), 2: 1–36.

Other research interests

I am also interested in the taxonomy of other families of Elateroidea and Byrrhoidea, including Cneoglossidae, Phengodidae, Omethidae (incl. Telegeusinae), Lampyridae and other odd balls within these superfamilies. Among the highlights of those research projects are the discovery and molecular placement of Chespirito Ferreira, Keller and Branham, a new subfamily of non-bioluminescent fireflies, and the development of a revision of Pseudotelegeusis Wittmer (near submission status).

Screen Shot 2022-01-21 at 11.03.40Phylogenetic placement of Chespirito among the Lampyridae based on molecular data.

Related publications
  1. Ferreira, V.S., Keller, O. and Branham, M.A. Multilocus Phylogeny Support the Non-Bioluminescent Firefly Chespirito as a New Subfamily in the Lampyridae (Coleoptera: Elateroidea). Insect Systematics and Diversity. 4(6): 1−3. 
  2. Ferreira, V.S., Keller, O., Branham, M.A. and Ivie, M.A. Molecular Data Support the Placement of the Enigmatic Cheguevaria Kazantsev as a subfamily of Lampyridae (Insecta: Coleoptera). Zoological Journal of the Linnean Society. 
  3. Ferreira, V.S., Keller, O. and Ivie, M.A. 2022. Descriptions of New Species of Chespirito Ferreira, Keller & Branham (Coleoptera: Lampyridae: Chespiritoinae) and the First Record for the Subfamily in the United States. Zootaxa. 5124 (2): 230–237. 
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