Lamprohiza mulsantii Kiesenwetter, 1850 

The larva is small and elliptical and can be seen at night during Spring and Summer, amongst the leaflitter on the soil of humid riverside woods. 

It has a beige underside and its back is dark brown, slightly shiny with some bright dots, which means it is very well camouflaged and looks like the leaf litter in which it lives. 

The Lamprohiza genus has a different light organ distribution pattern from other species: they vary in number (between 3 and 10, sometimes even more), spread along the lateral sides of the abdominal segments. 

L. mulsantii larvae and females also shows light organs in the metathoracic segment and the 6th, 7th and 8th abdominal segments: in other Lamprohiza species, these segments don’t bear light organs. This makes an excellent feature to identify the larvae and females of Mulsanti’s glow-worm. 

Behaviour and where to observe 

Females are coloured typically yellowish white, like ivory, and they stay on the ground among the leaf litter and emit a continuous glow. The light organ pattern is due to the various light spots spread throughout their abdomen, inherited from the larval phase, and two extra kidney-shaped adult light organs in 2 ventral segments (5th and 6th abdominal segments), which are very similar to the adult light organs found in female L. paulinoi (except that this latter species shows fewer light spots in the terminal area). The wingless females only bear vestigial elytra. The males however are winged and flighted and look for the glowing females. 

Adult female: Has small pairs of light spots along the body outline and her permanent glow can be seen during the night, on the ground, plants or on walls. Like all Lamprohiza females she lifts her abdomen up dorsally to expose the bright ventral adult lanterns. Adult females are mostly white and telling them apart from L. paulinoi can be difficult. L. mulsantii females are usually smaller in size, more white in colour and show the extra lateral light spots in the ultimate abdominal segments. 

Adult males: Similar to Lampyris noctiluca males in shape and colour but much smaller and they have these very distinguishable clear transparent spots in the pronotum (eye windows) – typical of the genus Lamprohiza – that in adult Lampyris are absent or just translucent (never transparent!). Contrary to the generally larger and paler L. paulinoi males, male L. mulsantii have more rounded elytral sides, especially towards the end of the elytra, what gives them a more oval overall shape. They don’t emit light, even not when disturbed (Except perhaps very young males that still have some vestigial lateral larval glow organs which disappear with age).

Size 

Larva: 4 to 13mm. Adult Male: 8 to 10mm. 

Adult Female: 8 to 12mm. 

Trivia 

Occurs in Portugal and the Parque Biológico de Gaia was one of the sites that supplied the specimens which led to the discovery that this species also exists in Portugal. It is also present in Catalonia in Spain and South-Western France from the Pyrenees, Toulouse region even up till central and almost Paris.

Text and photos - «Fireflies and Glow-worms of Portugal», 2015, ISBN n.º 978-989-98330-9-8.