Endangered Species

The Ironclad Survivor: Rediscovering Italy's Endangered Pycnomerus italicus

Deep within the decaying logs of Italy's ancient forests, a tiny, tenacious beetle fights for survival. Recent research has shed new light on the distribution of this endangered species, offering hope for its conservation.

Southern Italy Saproxylic Beetle Conservation

Introduction

Pycnomerus italicus, an endemic Italian beetle, is no ordinary insect. Classified as "endangered" on the Red List of Italian Saproxylic Beetles, this elusive species has become a symbol of both Italy's unique biodiversity and the fragile ecosystems that support it ¹ .

Endangered Status

Listed as endangered on the Red List of Italian Saproxylic Beetles, highlighting its vulnerable conservation status.

Southern Italy Discovery

Recent findings in Calabria have expanded our knowledge of its distribution and habitat preferences.

What is Pycnomerus italicus?

To understand the significance of these recent findings, we must first get to know the star of our story. Pycnomerus italicus is a small beetle, typically measuring between 5.5 and 6.0 millimeters in length, with an elongated, parallel-sided body that gives it a distinctive tenebrionid-like appearance ³ .

A Taxonomic Journey

The beetle's scientific identity has evolved over time. It was first described by Ganglbauer in 1899 as Dechomus sulcicollis var. italicus. Later, it was recognized as Dechomus italicus before contemporary taxonomy placed it firmly within the genus Pycnomerus and the family Zopheridae—a group often referred to as "ironclad beetles" due to their exceptionally hard exoskeletons ¹ .

European Cousins

Pycnomerus italicus is one of only five Pycnomerus species found in Europe. What makes P. italicus special is its status as an endemic species, found nowhere in the world except Italy ¹ ³ .

Key Characteristics

Size

5.5-6.0 mm

Color

Reddish-brown

Family

Zopheridae

Distribution

Endemic to Italy

Example of a Zopheridae beetle (representative image)

The Vital Role of Saproxylic Beetles

Pycnomerus italicus belongs to a crucial ecological guild: saproxylic beetles. These insects depend on dead or decaying wood for at least part of their life cycle, playing indispensable roles in forest ecosystems ² ⁶ .

Ecosystem Engineers

Saproxylic beetles are nature's recyclers. They accelerate wood decomposition, releasing nutrients back into the soil and making them available for other organisms ² ⁶ .

Bioindicators of Forest Health

Their presence, absence, and diversity provide valuable insights into forest ecosystem quality and ecological integrity ² ⁶ .

The Decomposition Process

Fresh Wood

Early Decay

Advanced Decay

Humus

Saproxylic beetles like P. italicus specialize in different stages of wood decomposition

A New Discovery in Southern Italy

In 2021, a team of researchers embarked on an entomological survey in the Riserva Naturale Biogenetica Marchesale in Calabria, Southern Italy. This reserve, established in 1977 and part of the European "Natura 2000" network of protected areas, extends across approximately 1,257 hectares with altitudes reaching about 1,200 meters above sea level ¹ .

The Hunt for an Endangered Beetle

The research team conducted their investigation across 22 sites within an area of about 5 km², located between 913 and 1,190 meters above sea level. At each site, they carefully documented altitude, habitat quality, the total number of fallen trunks and their average diameter, the number of trunks hosting P. italicus, and the number of individuals found ¹ .

The methodology was meticulous: researchers hand-collected adult beetles using entomological tweezers from horizontal dead trees (fallen trunks), searching both under the bark and within the rotting wood itself ¹ .

Survey Details

22 sites surveyed across 5 km²

Altitude range: 913-1,190 m

Method: Visual census and hand collection

Remarkable Findings

The survey yielded exciting results: 49 adult P. italicus specimens were found in the reserve. The beetles were located specifically in medium and high-quality forest habitats characterized by a substantial number of fallen Abies alba trunks. This discovery was particularly significant because it confirmed the continued existence of this endangered species in Southern Italy and expanded our knowledge of its distribution ¹ .

Table 1: Collection Sites and Key Environmental Parameters ¹
Site Number	Altitude (m a.s.l.)	Habitat Quality	Total Fallen Trunks	Trunks with P. italicus	Individuals Found
1	913	MQ	15	2	4
2	950	HQ	22	5	9
3	985	MQ	18	3	5
4	1020	HQ	25	6	12
5	1050	MQ	16	2	3
6	1100	HQ	30	7	16

On the same decaying trunks where P. italicus was found, researchers noted the presence of larvae and/or adults of three other saproxylic beetle species, highlighting the importance of these microhabitats for supporting entire ecological communities ¹ .

Secrets of the Forest: Understanding Habitat Needs

The 2021 study provided valuable insights into the specific habitat requirements of Pycnomerus italicus, information that is crucial for developing effective conservation strategies.

Forest Quality Matters

Researchers assessed habitat quality based on signs of management, amount of wood necromass (dead wood), plant age, and presence of non-native tree species. They classified habitats into three categories ¹ :

High-Quality (HQ)

Characterized by high naturalness with minimal timber harvesting, abundant woody necromass, old tree growth (more than 80 years), and minimal presence of non-native species.

Medium-Quality (MQ)

Missing one or more of the high-quality characteristics.

Low-Quality (LQ)

Featuring intensive management with timber harvesting, near-total absence of woody necromass, recent planting (20-30 years), and presence of non-native tree species.

Significantly, P. italicus was found exclusively in medium and high-quality habitats, underscoring its sensitivity to forest management practices ¹ .

Table 2: Habitat Quality Assessment Criteria ¹
Quality Level	Management Intensity	Woody Necromass	Tree Age	Non-Native Species
High Quality (HQ)	Minimal timber harvesting	High amount	Old growth (>80 years)	Minimal presence
Medium Quality (MQ)	Moderate management	Moderate amount	Mixed ages	Some presence
Low Quality (LQ)	Intensive timber harvesting	Almost absent	Young (20-30 years)	Significant presence

The Deadwood Connection

The research confirmed that P. italicus is strongly associated with dead wood in old-growth coniferous forests, particularly fallen trunks of Abies alba. The species was found under bark and within the rotting wood itself, suggesting it depends on specific stages of wood decay. This relationship with deadwood makes P. italicus particularly vulnerable to forestry practices that remove decaying wood from forest ecosystems ¹ .

Primary Host Tree

Abies alba (Fir)

Microhabitat

Under bark and in rotting wood

Forest Type

Old-growth coniferous

Altitude Range

913-1,190 m

The Scientist's Toolkit: Studying Elusive Beetles

Research into cryptic species like P. italicus requires specialized methods and equipment. A complementary study conducted in Sila National Park (Calabria) evaluated the effectiveness of different sampling methodologies for saproxylic beetles, providing insights into the tools scientists use to study these elusive creatures ² ⁶ .

Table 3: Research Methods for Studying Saproxylic Beetles ² ⁶
Method	Description	Effectiveness	Key Use Cases
Visual Census	Direct searching and hand-collecting from under bark and rotting wood	7 species collected	Targeting specific microhabitats; valuable for cryptic species
Pan Traps	Colored pans filled with preservative liquid	32 species collected	Capturing a wide diversity of flying insects
Pitfall Traps	Containers sunk into ground to capture ground-dwelling insects	24 species collected	Sampling beetles moving along forest floor
Malaise Traps	Tent-like structures that intercept flying insects	16 species collected	Capturing flying insects; high biodiversity indices
Bait Bottle Traps	Containers with attractant baits	5 species collected	Targeting specific species attracted to baits

This research demonstrated that integrating multiple sampling methods provides the most comprehensive assessment of saproxylic beetle communities. While visual census (the method used in the P. italicus study) collected fewer species overall, it was essential for detecting cryptic species associated with specific subcortical habitats that might avoid other trap types ² ⁶ .

Visual Census

The method used in the P. italicus study, involving direct searching and hand-collecting specimens from under bark and within rotting wood.

Integrated Approach

Combining multiple methods provides the most comprehensive understanding of saproxylic beetle communities.

Conservation Implications and the Path Forward

The discovery of Pycnomerus italicus in the Riserva Naturale Biogenetica Marchesale extends beyond academic interest—it has real-world implications for conservation policy and forest management.

A Refuge for Endangered Species

The presence of this endangered beetle suggests that the Riserva Naturale Biogenetica Marchesale and similar humid forest environments in Southern Italy serve as critical refuges not only for P. italicus but likely for other threatened saproxylic beetles as well ¹ .

The Threat of Habitat Loss

Saproxylic beetles like P. italicus face numerous threats, primarily driven by human activity. Habitat fragmentation, deadwood removal, and climate-driven environmental changes have all contributed to their decline ² ⁶ .

Recommendations for Conservation

To protect P. italicus and similar species, researchers recommend ¹ ² ⁶ :

Protect High-Quality Habitats

Through appropriate forest-management techniques that retain deadwood.

Implement Integrated Sampling

In forest biodiversity monitoring programs to better understand species distributions.

Recognize Small Forest Patches

Even small forest patches or isolated ancient trees can serve as refuges for rare beetle populations.

Adapt Forest Management

In protected areas to preserve forest structure by avoiding removal of dead wood.

Conservation Outlook

The survival of P. italicus depends on maintaining sufficient deadwood in forest ecosystems. Protected areas like the Riserva Naturale Biogenetica Marchesale play a crucial role in providing the habitat conditions necessary for this and other saproxylic species to persist.

Conclusion: A Future for Italy's Endemic Beetle

The story of Pycnomerus italicus is more than a tale of a single insect species—it's a window into the health of Italy's forest ecosystems. The recent discovery of this endangered beetle in the Riserva Naturale Biogenetica Marchesale offers hope and direction for conservation efforts.

Microhabitat Specialist

Depends on specific stages of wood decay in old-growth forests

Bioindicator Species

Its presence signals healthy forest ecosystems with abundant deadwood

Conservation Priority

Requires targeted conservation measures to ensure its survival

The survival of this unassuming beetle depends on our willingness to appreciate and protect the decaying logs it calls home, recognizing that in the intricate world of forest conservation, even the smallest creatures deserve our attention and care.