Chris Packham has criticised Ant and Dec for ignoring his call to stop using creatures on I'm A Celebrity's Bushtucker Trials.
The Springwatch host, 58, previously penned an open letter saying teaching young viewers that killing for "exploitative 'entertainment'" was unacceptable.
Now Packham has told the Daily Star Sunday newspaper: "Every year, for the past five years, I've written to the producers of the programme complaining about the way they stereotype animals and abuse them. I always write to them and I've never had a reply.
"I then published an open letter in Radio Times asking for a personal reply from Ant and Dec. They didn't reply."
The show is famous for its trials, featuring bugs, rats, snakes and spiders.
Packham said of I'm A Celebrity ... Get Me Out Of Here! bosses: "I think they still believe that a significant part of the audience are titillated by animals being abused. But that is wrong ...
"We've done away with circuses and dolphinariums. The way we think about animals is changing very rapidly and it's time I'm A Celebrity caught up."
ITV has said the show "complies with all regional and national laws concerning the use of insects, animals and reptiles".
Ant and Dec are back hosting the show, and posted a selfie on Instagram from Australia with the caption "G'day".
Olympian Caitlyn Jenner, who revealed her identity as a trans woman in 2015, DJ Adele Roberts, pundit Ian Wright, singer Nadine Coyle and Corrie's Andrew Whyment are among those taking part this year.
Ant was replaced by Holly Willoughby last year, after pulling out from presenting following his arrest for drink-driving.