There are plenty of pink ladybug invitations available commercially either complemented with brown or black. You could choose from these or make one of your own and tweak it with the background that you prefer.
Decorate the party area in shades of pink, black or brown, and white. Have a giant ladybug made of balloons floating in the center of the room. Swath streamers all over the room in pink, black or brown, and white. Have topiary lollipop trees dotted around the room and stick big paper ladybugs in them. Light up the trees using pink and white fairy lights. Hang pink and white Chinese paper lanterns on the ceiling and change the light bulbs to pink.
Think of the tables as giant ladybugs. Cover them with a soft pink tablecloth and use black or brown plates for the dots. Cut out a large white and pink flower for the center and put a clear goldfish bowl in the middle. Fill it with pink and white clear marbles and arrange brown and soft pink flowers in it in a dome shape. Surround this with little tea lights in pink glass votive containers.
Decorate the buffet table like a garden. Cover it with a light green cloth and flowers cut from pink and white paper. Scatter little ladybug toys and pink flat-backed glass marbles around. Serve food on pink or white platters. At the back of the buffet table, have a topiary group made with pink flowers like gerberas. Stick paper ladybugs on and some crystal beads to add sparkle.
Serve mostly pink and dark brown colored food for the pink ladybug baby shower. Ham or smoked salmon sandwiches made with wholewheat bread and beet tinted pasta with a creamy tomato-red pepper sauce make really light choices. Have a ladybug sundae bar for dessert, with choices of strawberry or cherry ice cream and hot fudge or strawberry sauces, mixed red berries, whipped cream, and mini chocolate chips and light and dark brown MMs. For beverages, serve iced tea and pink lemonade.
Have a different kind of cake with a tower of strawberry and cherry French macarons decorated with melted chocolate to look like pink ladybugs. These little morsels make a different kind of sweet ending with coffee of tea.
Favors are really simple for the pink ladybug baby shower. There
are a lot of toiletries that can be made personal with a great pink
ladybug sticker. Scented candles in a tin, lip balms, or tiny cologne
sprays could all be made different just with a sticker. There are
also candies that look like ladybugs, either because of their foil
coverings or because they are decorated to look like ladybugs. Packed
into soft pink bags dotted with brown or black beads, they are sweet,
feminine, and perfect.