An Italian father and his son have been fined 60 million Sri Lankan rupees ($200,000; £150,000) for trying to smuggle hundreds of endemic insects – including 92 species of butterflies – out of a safari park.

Rangers at Yala National Park arrested Luigi Ferrari, 68, and his 28-year-old son Mattia on 8 May this year after they were found with jars containing the insects.

The men had lured the insects with animal attractants and planned on using wax sachets to chemically preserve them, investigations show.

They were convicted in early September of illegal collection, possession and transportation of the insects, and handed the highest-ever fine for wildlife crime in the country.

One of the park rangers, K Sujeewa Nishantha, told BBC Sinhala that on the day of the incident, a safari jeep driver had informed his team of rangers that a “suspicious car” was parked along the road, and that the two men who were in it had ventured into the forest with insect nets.

The rangers located the car and found hundreds of jars containing the insects in its trunk.

“All the insects were dead when we found them. They put a chemical in the bottles,” Mr Nishantha said. “There were more than three hundred animals.”

The men were initially slapped with 810 charges, but these were later reduced to 304. They could face two years in jail if they fail to pay the fine by 24 September.

Italian news reports say the men were on vacation in Sri Lanka at the time and have been held in the country since the incident.

Yala National Park, located in the country’s south-east, is one of Sri Lanka’s most popular wildlife parks, home to a high concentration of leopards, elephants and buffalos, among other animals.

Luigi Ferrari, an orthopaedic surgeon who specialises in treating foot and ankle injuries, was described by his friends as an insect enthusiast, reports say. He is also a member of an entomology association in Modena, a city in the north of Italy.

His friends and colleagues in Italy have pleaded for leniency on his behalf. Some suggested that the butterflies found in his possession have no commercial value, Italian daily Corriere della Sera reported.

Dr. Jagath Gunawardena, an expert on environmental law, told the BBC Sinhala that the $200,000 fine was a warning to criminals as well as a good precedent.

Additional reporting by BBC Sinhala